diff --git a/stdlib/_collections_abc.pyi b/stdlib/_collections_abc.pyi
index 363098df8058..720adc581f39 100644
--- a/stdlib/_collections_abc.pyi
+++ b/stdlib/_collections_abc.pyi
@@ -66,7 +66,7 @@ if sys.version_info < (3, 15):
 if sys.version_info >= (3, 12):
     __all__ += ["Buffer"]
 
-_KT_co = TypeVar("_KT_co", covariant=True)  # Key type covariant containers.
+_KT_co = TypeVar("_KT_co", bound=Hashable, covariant=True)  # Key type covariant containers.
 _VT_co = TypeVar("_VT_co", covariant=True)  # Value type covariant containers.
 
 @final
@@ -75,7 +75,7 @@ class dict_keys(KeysView[_KT_co], Generic[_KT_co, _VT_co]):  # undocumented
     def __reversed__(self) -> Iterator[_KT_co]: ...
     __hash__: ClassVar[None]  # type: ignore[assignment]
     if sys.version_info >= (3, 13):
-        def isdisjoint(self, other: Iterable[_KT_co], /) -> bool: ...
+        def isdisjoint(self, other: Iterable[Hashable], /) -> bool: ...
 
     @property
     def mapping(self) -> MappingProxyType[_KT_co, _VT_co]: ...
@@ -92,7 +92,7 @@ class dict_items(ItemsView[_KT_co, _VT_co]):  # undocumented
     def __reversed__(self) -> Iterator[tuple[_KT_co, _VT_co]]: ...
     __hash__: ClassVar[None]  # type: ignore[assignment]
     if sys.version_info >= (3, 13):
-        def isdisjoint(self, other: Iterable[tuple[_KT_co, _VT_co]], /) -> bool: ...
+        def isdisjoint(self, other: Iterable[Hashable], /) -> bool: ...
 
     @property
     def mapping(self) -> MappingProxyType[_KT_co, _VT_co]: ...
diff --git a/stdlib/_decimal.pyi b/stdlib/_decimal.pyi
index 75d5be277f95..4e231e8e53e5 100644
--- a/stdlib/_decimal.pyi
+++ b/stdlib/_decimal.pyi
@@ -58,8 +58,8 @@ if sys.version_info >= (3, 11):
         Emax: int | None = None,
         capitals: int | None = None,
         clamp: int | None = None,
-        traps: dict[_TrapType, bool] | None = None,
-        flags: dict[_TrapType, bool] | None = None,
+        traps: dict[_TrapType, bool] | None = None,  # type: ignore[type-var]
+        flags: dict[_TrapType, bool] | None = None,  # type: ignore[type-var]
     ) -> _ContextManager: ...
 
 else:
diff --git a/stdlib/_typeshed/__init__.pyi b/stdlib/_typeshed/__init__.pyi
index fa6ef8150e3a..dab48f180a51 100644
--- a/stdlib/_typeshed/__init__.pyi
+++ b/stdlib/_typeshed/__init__.pyi
@@ -295,9 +295,13 @@ OpenBinaryMode: TypeAlias = OpenBinaryModeUpdating | OpenBinaryModeReading | Ope
 class HasFileno(Protocol):
     def fileno(self) -> int: ...
 
+class HasFilenoAndHash(HasFileno, Protocol):
+    def __hash__(self) -> int: ...
+
 FileDescriptor: TypeAlias = int  # stable
 FileDescriptorLike: TypeAlias = int | HasFileno  # stable
 FileDescriptorOrPath: TypeAlias = int | StrOrBytesPath
+HashableFDLike: TypeAlias = int | HasFilenoAndHash
 
 # stable
 class SupportsRead(Protocol[_T_co]):
diff --git a/stdlib/_weakrefset.pyi b/stdlib/_weakrefset.pyi
index 82ffa4463f48..611ebd68be3b 100644
--- a/stdlib/_weakrefset.pyi
+++ b/stdlib/_weakrefset.pyi
@@ -1,4 +1,4 @@
-from collections.abc import Iterable, Iterator, MutableSet
+from collections.abc import Hashable, Iterable, Iterator, MutableSet
 from types import GenericAlias
 from typing import Any, ClassVar, TypeVar, overload
 from typing_extensions import Self
@@ -6,7 +6,7 @@ from typing_extensions import Self
 __all__ = ["WeakSet"]
 
 _S = TypeVar("_S")
-_T = TypeVar("_T")
+_T = TypeVar("_T", bound=Hashable)
 
 class WeakSet(MutableSet[_T]):
     @overload
@@ -32,12 +32,12 @@ class WeakSet(MutableSet[_T]):
     def __and__(self, other: Iterable[Any]) -> Self: ...
     def intersection_update(self, other: Iterable[Any]) -> None: ...
     def __iand__(self, other: Iterable[Any]) -> Self: ...
-    def issubset(self, other: Iterable[_T]) -> bool: ...
-    def __le__(self, other: Iterable[_T]) -> bool: ...
-    def __lt__(self, other: Iterable[_T]) -> bool: ...
-    def issuperset(self, other: Iterable[_T]) -> bool: ...
-    def __ge__(self, other: Iterable[_T]) -> bool: ...
-    def __gt__(self, other: Iterable[_T]) -> bool: ...
+    def issubset(self, other: Iterable[Any]) -> bool: ...
+    def __le__(self, other: Iterable[Any]) -> bool: ...
+    def __lt__(self, other: Iterable[Any]) -> bool: ...
+    def issuperset(self, other: Iterable[Any]) -> bool: ...
+    def __ge__(self, other: Iterable[Any]) -> bool: ...
+    def __gt__(self, other: Iterable[Any]) -> bool: ...
     def __eq__(self, other: object) -> bool: ...
     def symmetric_difference(self, other: Iterable[_S]) -> WeakSet[_S | _T]: ...
     def __xor__(self, other: Iterable[_S]) -> WeakSet[_S | _T]: ...
@@ -45,5 +45,5 @@ class WeakSet(MutableSet[_T]):
     def __ixor__(self, other: Iterable[_T]) -> Self: ...  # type: ignore[override,misc]
     def union(self, other: Iterable[_S]) -> WeakSet[_S | _T]: ...
     def __or__(self, other: Iterable[_S]) -> WeakSet[_S | _T]: ...
-    def isdisjoint(self, other: Iterable[_T]) -> bool: ...
+    def isdisjoint(self, other: Iterable[Any]) -> bool: ...
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
diff --git a/stdlib/builtins.pyi b/stdlib/builtins.pyi
index 1f16114ed00f..12183899cf51 100644
--- a/stdlib/builtins.pyi
+++ b/stdlib/builtins.pyi
@@ -76,7 +76,7 @@ _I = TypeVar("_I", default=int)
 _T_co = TypeVar("_T_co", covariant=True)
 _T_contra = TypeVar("_T_contra", contravariant=True)
 _R_co = TypeVar("_R_co", covariant=True)
-_KT = TypeVar("_KT")
+_KT = TypeVar("_KT", bound=Hashable)
 _VT = TypeVar("_VT")
 _S = TypeVar("_S")
 _T1 = TypeVar("_T1")
@@ -84,6 +84,10 @@ _T2 = TypeVar("_T2")
 _T3 = TypeVar("_T3")
 _T4 = TypeVar("_T4")
 _T5 = TypeVar("_T5")
+_H1 = TypeVar("_H1", bound=Hashable)
+_H2 = TypeVar("_H2", bound=Hashable)
+_H1_co = TypeVar("_H1_co", bound=Hashable, covariant=True)
+
 _SupportsNextT_co = TypeVar("_SupportsNextT_co", bound=SupportsNext[Any], covariant=True)
 _SupportsAnextT_co = TypeVar("_SupportsAnextT_co", bound=SupportsAnext[Any], covariant=True)
 _AwaitableT = TypeVar("_AwaitableT", bound=Awaitable[Any])
@@ -1336,10 +1340,10 @@ class dict(MutableMapping[_KT, _VT]):
     # See #3800 & https://github.com/python/typing/issues/548#issuecomment-683336963.
     @classmethod
     @overload
-    def fromkeys(cls, iterable: Iterable[_T], value: None = None, /) -> dict[_T, Any | None]: ...
+    def fromkeys(cls, iterable: Iterable[_H1], value: None = None, /) -> dict[_H1, Any | None]: ...
     @classmethod
     @overload
-    def fromkeys(cls, iterable: Iterable[_T], value: _S, /) -> dict[_T, _S]: ...
+    def fromkeys(cls, iterable: Iterable[_H1], value: _T, /) -> dict[_H1, _T]: ...
 
     # Positional-only in dict, but not in MutableMapping
     @overload  # type: ignore[override]
@@ -1366,16 +1370,15 @@ class dict(MutableMapping[_KT, _VT]):
     __hash__: ClassVar[None]  # type: ignore[assignment]
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
     if sys.version_info >= (3, 15):
-        def __or__(self, value: dict[_T1, _T2] | frozendict[_T1, _T2], /) -> dict[_KT | _T1, _VT | _T2]: ...
+        def __or__(self, value: dict[_H1, _T] | frozendict[_H1, _T], /) -> dict[_KT | _H1, _VT | _T]: ...
 
         @overload
-        def __ror__(self, value: dict[_T1, _T2], /) -> dict[_KT | _T1, _VT | _T2]: ...
+        def __ror__(self, value: dict[_H1, _T], /) -> dict[_KT | _H1, _VT | _T]: ...
         @overload
-        def __ror__(self, value: frozendict[_T1, _T2], /) -> frozendict[_KT | _T1, _VT | _T2]: ...
-
+        def __ror__(self, value: frozendict[_H1, _T], /) -> frozendict[_KT | _H1, _VT | _T]: ...
     else:
-        def __or__(self, value: dict[_T1, _T2], /) -> dict[_KT | _T1, _VT | _T2]: ...
-        def __ror__(self, value: dict[_T1, _T2], /) -> dict[_KT | _T1, _VT | _T2]: ...
+        def __or__(self, value: dict[_H1, _T], /) -> dict[_KT | _H1, _VT | _T]: ...
+        def __ror__(self, value: dict[_H1, _T], /) -> dict[_KT | _H1, _VT | _T]: ...
 
     # dict.__ior__ should be kept roughly in line with MutableMapping.update()
     @overload  # type: ignore[misc]
@@ -1387,7 +1390,7 @@ if sys.version_info >= (3, 15):
     @disjoint_base
     class frozendict(Mapping[_KT, _VT]):
         @overload
-        def __new__(cls, /) -> frozendict[Any, Any]: ...
+        def __new__(cls, /) -> frozendict[Hashable, Any]: ...
         @overload
         def __new__(cls: type[frozendict[str, _VT]], /, **kwargs: _VT) -> frozendict[str, _VT]: ...
         @overload
@@ -1407,10 +1410,10 @@ if sys.version_info >= (3, 15):
 
         @overload
         @classmethod
-        def fromkeys(cls, iterable: Iterable[_T], value: None = None, /) -> frozendict[_T, Any | None]: ...
+        def fromkeys(cls, iterable: Iterable[_H1], value: None = None, /) -> frozendict[_H1, Any | None]: ...
         @overload
         @classmethod
-        def fromkeys(cls, iterable: Iterable[_T], value: _S, /) -> frozendict[_T, _S]: ...
+        def fromkeys(cls, iterable: Iterable[_H1], value: _T, /) -> frozendict[_H1, _T]: ...
 
         @overload  # type: ignore[override]
         def get(self, key: _KT, default: None = None, /) -> _VT | None: ...
@@ -1436,120 +1439,120 @@ if sys.version_info >= (3, 15):
         def __ror__(self, value: frozendict[_T1, _T2], /) -> frozendict[_KT | _T1, _VT | _T2]: ...
 
 @disjoint_base
-class set(MutableSet[_T]):
+class set(MutableSet[_H1]):
     @overload
     def __init__(self) -> None: ...
     @overload
-    def __init__(self, iterable: Iterable[_T], /) -> None: ...
-
-    def add(self, element: _T, /) -> None: ...
-    def copy(self) -> set[_T]: ...
-    def difference(self, *s: Iterable[object]) -> set[_T]: ...
-    def difference_update(self, *s: Iterable[object]) -> None: ...
-    def discard(self, element: object, /) -> None: ...
-    def intersection(self, *s: Iterable[object]) -> set[_T]: ...
-    def intersection_update(self, *s: Iterable[object]) -> None: ...
-    def isdisjoint(self, s: Iterable[object], /) -> bool: ...
-    def issubset(self, s: Iterable[object], /) -> bool: ...
-    def issuperset(self, s: Iterable[object], /) -> bool: ...
-    def remove(self, element: _T, /) -> None: ...
-    def symmetric_difference(self, s: Iterable[_S], /) -> set[_T | _S]: ...
-    def symmetric_difference_update(self, s: Iterable[_T], /) -> None: ...
-    def union(self, *s: Iterable[_S]) -> set[_T | _S]: ...
-    def update(self, *s: Iterable[_T]) -> None: ...
+    def __init__(self, iterable: Iterable[_H1], /) -> None: ...
+
+    def add(self, element: _H1, /) -> None: ...
+    def copy(self) -> set[_H1]: ...
+    def difference(self, *s: Iterable[Hashable]) -> set[_H1]: ...
+    def difference_update(self, *s: Iterable[Hashable]) -> None: ...
+    def discard(self, element: Hashable, /) -> None: ...
+    def intersection(self, *s: Iterable[Hashable]) -> set[_H1]: ...
+    def intersection_update(self, *s: Iterable[Hashable]) -> None: ...
+    def isdisjoint(self, s: Iterable[Hashable], /) -> bool: ...
+    def issubset(self, s: Iterable[Hashable], /) -> bool: ...
+    def issuperset(self, s: Iterable[Hashable], /) -> bool: ...
+    def remove(self, element: _H1, /) -> None: ...
+    def symmetric_difference(self, s: Iterable[_H2], /) -> set[_H1 | _H2]: ...
+    def symmetric_difference_update(self, s: Iterable[_H1], /) -> None: ...
+    def union(self, *s: Iterable[_H2]) -> set[_H1 | _H2]: ...
+    def update(self, *s: Iterable[_H1]) -> None: ...
     def __len__(self) -> int: ...
-    def __contains__(self, o: object, /) -> bool: ...
-    def __iter__(self) -> Iterator[_T]: ...
-    def __and__(self, value: AbstractSet[object], /) -> set[_T]: ...
-    def __iand__(self, value: AbstractSet[object], /) -> Self: ...
+    def __contains__(self, o: Hashable, /) -> bool: ...
+    def __iter__(self) -> Iterator[_H1]: ...
+    def __and__(self, value: AbstractSet[Hashable], /) -> set[_H1]: ...
+    def __iand__(self, value: AbstractSet[Hashable], /) -> Self: ...
 
     @overload
-    def __rand__(self, value: set[_S], /) -> set[_S]: ...
+    def __rand__(self, value: set[_H2], /) -> set[_H2]: ...
     @overload
-    def __rand__(self, value: frozenset[_S], /) -> frozenset[_S]: ...
+    def __rand__(self, value: frozenset[_H2], /) -> frozenset[_H2]: ...
 
-    def __or__(self, value: AbstractSet[_S], /) -> set[_T | _S]: ...
-    def __ior__(self, value: AbstractSet[_T], /) -> Self: ...  # type: ignore[override,misc]
+    def __or__(self, value: AbstractSet[_H2], /) -> set[_H1 | _H2]: ...
+    def __ior__(self, value: AbstractSet[_H1], /) -> Self: ...  # type: ignore[override,misc]
 
     @overload
-    def __ror__(self, value: set[_S], /) -> set[_T | _S]: ...
+    def __ror__(self, value: set[_H2], /) -> set[_H1 | _H2]: ...
     @overload
-    def __ror__(self, value: frozenset[_S], /) -> frozenset[_T | _S]: ...
+    def __ror__(self, value: frozenset[_H2], /) -> frozenset[_H1 | _H2]: ...
 
-    def __sub__(self, value: AbstractSet[object], /) -> set[_T]: ...
-    def __isub__(self, value: AbstractSet[object], /) -> Self: ...
+    def __sub__(self, value: AbstractSet[Hashable], /) -> set[_H1]: ...
+    def __isub__(self, value: AbstractSet[Hashable], /) -> Self: ...
 
     @overload
-    def __rsub__(self, value: set[_S], /) -> set[_S]: ...
+    def __rsub__(self, value: set[_H2], /) -> set[_H2]: ...
     @overload
-    def __rsub__(self, value: frozenset[_S], /) -> frozenset[_S]: ...
+    def __rsub__(self, value: frozenset[_H2], /) -> frozenset[_H2]: ...
 
-    def __xor__(self, value: AbstractSet[_S], /) -> set[_T | _S]: ...
-    def __ixor__(self, value: AbstractSet[_T], /) -> Self: ...  # type: ignore[override,misc]
+    def __xor__(self, value: AbstractSet[_H2], /) -> set[_H1 | _H2]: ...
+    def __ixor__(self, value: AbstractSet[_H1], /) -> Self: ...  # type: ignore[override,misc]
 
     @overload
-    def __rxor__(self, value: set[_S], /) -> set[_T | _S]: ...
+    def __rxor__(self, value: set[_H2], /) -> set[_H1 | _H2]: ...
     @overload
-    def __rxor__(self, value: frozenset[_S], /) -> frozenset[_T | _S]: ...
+    def __rxor__(self, value: frozenset[_H2], /) -> frozenset[_H1 | _H2]: ...
 
-    def __le__(self, value: AbstractSet[object], /) -> bool: ...
-    def __lt__(self, value: AbstractSet[object], /) -> bool: ...
-    def __ge__(self, value: AbstractSet[object], /) -> bool: ...
-    def __gt__(self, value: AbstractSet[object], /) -> bool: ...
+    def __le__(self, value: AbstractSet[Hashable], /) -> bool: ...
+    def __lt__(self, value: AbstractSet[Hashable], /) -> bool: ...
+    def __ge__(self, value: AbstractSet[Hashable], /) -> bool: ...
+    def __gt__(self, value: AbstractSet[Hashable], /) -> bool: ...
     def __eq__(self, value: object, /) -> bool: ...
     __hash__: ClassVar[None]  # type: ignore[assignment]
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
 
 @disjoint_base
-class frozenset(AbstractSet[_T_co]):
+class frozenset(AbstractSet[_H1_co]):
     @overload
     def __new__(cls) -> Self: ...
     @overload
-    def __new__(cls, iterable: Iterable[_T_co], /) -> Self: ...
+    def __new__(cls, iterable: Iterable[_H1_co], /) -> Self: ...
 
-    def copy(self) -> frozenset[_T_co]: ...
-    def difference(self, *s: Iterable[object]) -> frozenset[_T_co]: ...
-    def intersection(self, *s: Iterable[object]) -> frozenset[_T_co]: ...
-    def isdisjoint(self, s: Iterable[object], /) -> bool: ...
-    def issubset(self, s: Iterable[object], /) -> bool: ...
-    def issuperset(self, s: Iterable[object], /) -> bool: ...
-    def symmetric_difference(self, s: Iterable[_S], /) -> frozenset[_T_co | _S]: ...
-    def union(self, *s: Iterable[_S]) -> frozenset[_T_co | _S]: ...
+    def copy(self) -> frozenset[_H1_co]: ...
+    def difference(self, *s: Iterable[Hashable]) -> frozenset[_H1_co]: ...
+    def intersection(self, *s: Iterable[Hashable]) -> frozenset[_H1_co]: ...
+    def isdisjoint(self, s: Iterable[Hashable], /) -> bool: ...
+    def issubset(self, s: Iterable[Hashable], /) -> bool: ...
+    def issuperset(self, s: Iterable[Hashable], /) -> bool: ...
+    def symmetric_difference(self, s: Iterable[_H1], /) -> frozenset[_H1_co | _H1]: ...
+    def union(self, *s: Iterable[_H1]) -> frozenset[_H1_co | _H1]: ...
     def __len__(self) -> int: ...
-    def __contains__(self, o: object, /) -> bool: ...
-    def __iter__(self) -> Iterator[_T_co]: ...
-    def __and__(self, value: AbstractSet[object], /) -> frozenset[_T_co]: ...
+    def __contains__(self, o: Hashable, /) -> bool: ...
+    def __iter__(self) -> Iterator[_H1_co]: ...
+    def __and__(self, value: AbstractSet[Hashable], /) -> frozenset[_H1_co]: ...
 
     @overload
-    def __rand__(self, value: set[_S], /) -> set[_S]: ...
+    def __rand__(self, value: set[_H1], /) -> set[_H1]: ...
     @overload
-    def __rand__(self, value: frozenset[_S], /) -> frozenset[_S]: ...
+    def __rand__(self, value: frozenset[_H1], /) -> frozenset[_H1]: ...
 
-    def __or__(self, value: AbstractSet[_S], /) -> frozenset[_T_co | _S]: ...
+    def __or__(self, value: AbstractSet[_H1], /) -> frozenset[_H1_co | _H1]: ...
 
     @overload
-    def __ror__(self, value: set[_S], /) -> set[_T_co | _S]: ...
+    def __ror__(self, value: set[_H1], /) -> set[_H1_co | _H1]: ...
     @overload
-    def __ror__(self, value: frozenset[_S], /) -> frozenset[_T_co | _S]: ...
+    def __ror__(self, value: frozenset[_H1], /) -> frozenset[_H1_co | _H1]: ...
 
-    def __sub__(self, value: AbstractSet[object], /) -> frozenset[_T_co]: ...
+    def __sub__(self, value: AbstractSet[Hashable], /) -> frozenset[_H1_co]: ...
 
     @overload
-    def __rsub__(self, value: set[_S], /) -> set[_S]: ...
+    def __rsub__(self, value: set[_H1], /) -> set[_H1]: ...
     @overload
-    def __rsub__(self, value: frozenset[_S], /) -> frozenset[_S]: ...
+    def __rsub__(self, value: frozenset[_H1], /) -> frozenset[_H1]: ...
 
-    def __xor__(self, value: AbstractSet[_S], /) -> frozenset[_T_co | _S]: ...
+    def __xor__(self, value: AbstractSet[_H1], /) -> frozenset[_H1_co | _H1]: ...
 
     @overload
-    def __rxor__(self, value: set[_S], /) -> set[_T_co | _S]: ...
+    def __rxor__(self, value: set[_H1], /) -> set[_H1_co | _H1]: ...
     @overload
-    def __rxor__(self, value: frozenset[_S], /) -> frozenset[_T_co | _S]: ...
+    def __rxor__(self, value: frozenset[_H1], /) -> frozenset[_H1_co | _H1]: ...
 
-    def __le__(self, value: AbstractSet[object], /) -> bool: ...
-    def __lt__(self, value: AbstractSet[object], /) -> bool: ...
-    def __ge__(self, value: AbstractSet[object], /) -> bool: ...
-    def __gt__(self, value: AbstractSet[object], /) -> bool: ...
+    def __le__(self, value: AbstractSet[Hashable], /) -> bool: ...
+    def __lt__(self, value: AbstractSet[Hashable], /) -> bool: ...
+    def __ge__(self, value: AbstractSet[Hashable], /) -> bool: ...
+    def __gt__(self, value: AbstractSet[Hashable], /) -> bool: ...
     def __eq__(self, value: object, /) -> bool: ...
     def __hash__(self) -> int: ...
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
diff --git a/stdlib/collections/__init__.pyi b/stdlib/collections/__init__.pyi
index bce72464fd75..02d1d24d54a9 100644
--- a/stdlib/collections/__init__.pyi
+++ b/stdlib/collections/__init__.pyi
@@ -3,6 +3,7 @@ from _collections_abc import dict_items, dict_keys, dict_values
 from _typeshed import SupportsItems, SupportsKeysAndGetItem, SupportsRichComparison, SupportsRichComparisonT
 from collections.abc import (
     Callable,
+    Hashable,
     ItemsView,
     Iterable,
     Iterator,
@@ -22,16 +23,14 @@ if sys.version_info >= (3, 15):
 
 __all__ = ["ChainMap", "Counter", "OrderedDict", "UserDict", "UserList", "UserString", "defaultdict", "deque", "namedtuple"]
 
-_S = TypeVar("_S")
 _T = TypeVar("_T")
-_T1 = TypeVar("_T1")
-_T2 = TypeVar("_T2")
-_KT = TypeVar("_KT")
+_KT = TypeVar("_KT", bound=Hashable)
 _VT = TypeVar("_VT")
-_KT_co = TypeVar("_KT_co", covariant=True)
+_KT2 = TypeVar("_KT2")
+_KT_co = TypeVar("_KT_co", bound=Hashable, covariant=True)
 _VT_co = TypeVar("_VT_co", covariant=True)
 
-# namedtuple is special-cased in the type checker; the initializer is ignored.
+# namedtuple is special-cased in type checkers; the initializer is ignored.
 def namedtuple(
     typename: str,
     field_names: str | Iterable[str],
@@ -88,20 +87,20 @@ class UserDict(MutableMapping[_KT, _VT]):
     # See #3800 & https://github.com/python/typing/issues/548#issuecomment-683336963.
     @classmethod
     @overload
-    def fromkeys(cls, iterable: Iterable[_T], value: None = None) -> UserDict[_T, Any | None]: ...
+    def fromkeys(cls, iterable: Iterable[_KT], value: None = None) -> UserDict[_KT, Any | None]: ...
     @classmethod
     @overload
-    def fromkeys(cls, iterable: Iterable[_T], value: _S) -> UserDict[_T, _S]: ...
+    def fromkeys(cls, iterable: Iterable[_KT], value: _T) -> UserDict[_KT, _T]: ...
 
     @overload
     def __or__(self, other: UserDict[_KT, _VT] | dict[_KT, _VT]) -> Self: ...
     @overload
-    def __or__(self, other: UserDict[_T1, _T2] | dict[_T1, _T2]) -> UserDict[_KT | _T1, _VT | _T2]: ...
+    def __or__(self, other: UserDict[_KT2, _T] | dict[_KT2, _T]) -> UserDict[_KT | _KT2, _VT | _T]: ...
 
     @overload
     def __ror__(self, other: UserDict[_KT, _VT] | dict[_KT, _VT]) -> Self: ...
     @overload
-    def __ror__(self, other: UserDict[_T1, _T2] | dict[_T1, _T2]) -> UserDict[_KT | _T1, _VT | _T2]: ...
+    def __ror__(self, other: UserDict[_KT2, _T] | dict[_KT2, _T]) -> UserDict[_KT | _KT2, _VT | _T]: ...
 
     # UserDict.__ior__ should be kept roughly in line with MutableMapping.update()
     @overload  # type: ignore[misc]
@@ -290,67 +289,73 @@ class deque(MutableSequence[_T]):
     def __eq__(self, value: object, /) -> bool: ...
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
 
-class Counter(dict[_T, int], Generic[_T]):
+class Counter(dict[_KT, int], Generic[_KT]):
     @overload
     def __init__(self, iterable: None = None, /) -> None: ...
     @overload
     def __init__(self: Counter[str], iterable: None = None, /, **kwargs: int) -> None: ...
     @overload
-    def __init__(self, mapping: SupportsKeysAndGetItem[_T, int], /) -> None: ...
+    def __init__(self, mapping: SupportsKeysAndGetItem[_KT, int], /) -> None: ...
     @overload
-    def __init__(self, iterable: Iterable[_T], /) -> None: ...
+    def __init__(self, iterable: Iterable[_KT], /) -> None: ...
 
     def copy(self) -> Self: ...
-    def elements(self) -> Iterator[_T]: ...
-    def most_common(self, n: int | None = None) -> list[tuple[_T, int]]: ...
+    def elements(self) -> Iterator[_KT]: ...
+    def most_common(self, n: int | None = None) -> list[tuple[_KT, int]]: ...
     @classmethod
     def fromkeys(cls, iterable: Any, v: int | None = None) -> Never: ...  # type: ignore[override]
 
     @overload
     def subtract(self, iterable: None = None, /) -> None: ...
     @overload
-    def subtract(self, mapping: Mapping[_T, int], /) -> None: ...
+    def subtract(self, mapping: Mapping[_KT, int], /) -> None: ...
     @overload
-    def subtract(self, iterable: Iterable[_T], /) -> None: ...
+    def subtract(self, iterable: Iterable[_KT], /) -> None: ...
 
     # Unlike dict.update(), use Mapping instead of SupportsKeysAndGetItem for the first overload
     # (source code does an `isinstance(other, Mapping)` check)
     #
     # The second overload is also deliberately different to dict.update()
-    # (if it were `Iterable[_T] | Iterable[tuple[_T, int]]`,
+    # (if it were `Iterable[_KT] | Iterable[tuple[_KT, int]]`,
     # the tuples would be added as keys, breaking type safety)
     @overload  # type: ignore[override]
-    def update(self, m: Mapping[_T, int], /, **kwargs: int) -> None: ...
+    def update(self: Counter[str], m: Mapping[str, int], /, **kwargs: int) -> None: ...
     @overload
-    def update(self, iterable: Iterable[_T], /, **kwargs: int) -> None: ...
+    def update(self: Counter[str], iterable: Iterable[str], /, **kwargs: int) -> None: ...
     @overload
-    def update(self, iterable: None = None, /, **kwargs: int) -> None: ...
+    def update(self: Counter[str], iterable: None = None, /, **kwargs: int) -> None: ...
+    @overload
+    def update(self, m: Mapping[_KT, int], /) -> None: ...
+    @overload
+    def update(self, iterable: Iterable[_KT], /) -> None: ...
+    @overload
+    def update(self, iterable: None = None, /) -> None: ...
 
     def total(self) -> int: ...
-    def __missing__(self, key: _T) -> int: ...
-    def __delitem__(self, elem: object) -> None: ...
-    def __eq__(self, other: object) -> bool: ...
-    def __ne__(self, other: object) -> bool: ...
-    def __le__(self, other: Counter[Any]) -> bool: ...
-    def __lt__(self, other: Counter[Any]) -> bool: ...
-    def __ge__(self, other: Counter[Any]) -> bool: ...
-    def __gt__(self, other: Counter[Any]) -> bool: ...
-    def __add__(self, other: Counter[_S]) -> Counter[_T | _S]: ...
-    def __sub__(self, other: Counter[_T]) -> Counter[_T]: ...
-    def __and__(self, other: Counter[_T]) -> Counter[_T]: ...
-    def __or__(self, other: Counter[_S]) -> Counter[_T | _S]: ...  # type: ignore[override]
+    def __missing__(self, key: _KT) -> int: ...
+    def __delitem__(self, elem: Hashable) -> None: ...
+    def __eq__(self, other: Hashable) -> bool: ...
+    def __ne__(self, other: Hashable) -> bool: ...
+    def __le__(self, other: Counter[Hashable]) -> bool: ...
+    def __lt__(self, other: Counter[Hashable]) -> bool: ...
+    def __ge__(self, other: Counter[Hashable]) -> bool: ...
+    def __gt__(self, other: Counter[Hashable]) -> bool: ...
+    def __add__(self, other: Counter[_KT2]) -> Counter[_KT | _KT2]: ...
+    def __sub__(self, other: Counter[_KT]) -> Counter[_KT]: ...
+    def __and__(self, other: Counter[_KT]) -> Counter[_KT]: ...
+    def __or__(self, other: Counter[_KT2]) -> Counter[_KT | _KT2]: ...  # type: ignore[override]
     if sys.version_info >= (3, 15):
-        def __xor__(self, other: Counter[_S]) -> Counter[_T | _S]: ...  # type: ignore[override]
+        def __xor__(self, other: Counter[_KT2]) -> Counter[_KT | _KT2]: ...  # type: ignore[override]
 
-    def __pos__(self) -> Counter[_T]: ...
-    def __neg__(self) -> Counter[_T]: ...
+    def __pos__(self) -> Counter[_KT]: ...
+    def __neg__(self) -> Counter[_KT]: ...
     # several type: ignores because __iadd__ is supposedly incompatible with __add__, etc.
-    def __iadd__(self, other: SupportsItems[_T, int]) -> Self: ...  # type: ignore[misc]
-    def __isub__(self, other: SupportsItems[_T, int]) -> Self: ...
-    def __iand__(self, other: SupportsItems[_T, int]) -> Self: ...
-    def __ior__(self, other: SupportsItems[_T, int]) -> Self: ...  # type: ignore[override,misc]
+    def __iadd__(self, other: SupportsItems[_KT, int]) -> Self: ...  # type: ignore[misc]
+    def __isub__(self, other: SupportsItems[_KT, int]) -> Self: ...
+    def __iand__(self, other: SupportsItems[_KT, int]) -> Self: ...
+    def __ior__(self, other: SupportsItems[_KT, int]) -> Self: ...  # type: ignore[override,misc]
     if sys.version_info >= (3, 15):
-        def __ixor__(self, other: Counter[_T]) -> Self: ...  # type: ignore[misc]
+        def __ixor__(self, other: Counter[_KT]) -> Self: ...  # type: ignore[misc]
 
 # The pure-Python implementations of the "views" classes
 # These are exposed at runtime in `collections/__init__.py`
@@ -395,12 +400,12 @@ class OrderedDict(dict[_KT, _VT]):
     # The signature of OrderedDict.fromkeys should be kept in line with `dict.fromkeys`, modulo positional-only differences.
     # Like dict.fromkeys, its true signature is not expressible in the current type system.
     # See #3800 & https://github.com/python/typing/issues/548#issuecomment-683336963.
-    @classmethod
+    @classmethod  # type: ignore[override]
     @overload
-    def fromkeys(cls, iterable: Iterable[_T], value: None = None) -> OrderedDict[_T, Any | None]: ...
+    def fromkeys(cls, iterable: Iterable[_KT], value: None = None) -> OrderedDict[_KT, Any | None]: ...
     @classmethod
     @overload
-    def fromkeys(cls, iterable: Iterable[_T], value: _S) -> OrderedDict[_T, _S]: ...
+    def fromkeys(cls, iterable: Iterable[_KT], value: _T) -> OrderedDict[_KT, _T]: ...
 
     # Keep OrderedDict.setdefault in line with MutableMapping.setdefault, modulo positional-only differences.
     @overload
@@ -422,24 +427,24 @@ class OrderedDict(dict[_KT, _VT]):
         @overload
         def __or__(self, value: dict[_KT, _VT] | frozendict[_KT, _VT], /) -> Self: ...
         @overload
-        def __or__(self, value: dict[_T1, _T2] | frozendict[_T1, _T2], /) -> OrderedDict[_KT | _T1, _VT | _T2]: ...
+        def __or__(self, value: dict[_KT2, _T] | frozendict[_KT2, _T], /) -> OrderedDict[_KT | _KT2, _VT | _T]: ...
 
         @overload  # type: ignore[override]
         def __ror__(self, value: dict[_KT, _VT] | frozendict[_KT, _VT], /) -> Self: ...  # type: ignore[override,misc]
         @overload
         def __ror__(  # type: ignore[misc]
-            self, value: dict[_T1, _T2] | frozendict[_T1, _T2], /
-        ) -> OrderedDict[_KT | _T1, _VT | _T2]: ...
+            self, value: dict[_KT2, _T] | frozendict[_KT2, _T], /
+        ) -> OrderedDict[_KT | _KT2, _VT | _T]: ...
     else:
         @overload
         def __or__(self, value: dict[_KT, _VT], /) -> Self: ...
         @overload
-        def __or__(self, value: dict[_T1, _T2], /) -> OrderedDict[_KT | _T1, _VT | _T2]: ...
+        def __or__(self, value: dict[_KT2, _T], /) -> OrderedDict[_KT | _KT2, _VT | _T]: ...
 
         @overload
         def __ror__(self, value: dict[_KT, _VT], /) -> Self: ...
         @overload
-        def __ror__(self, value: dict[_T1, _T2], /) -> OrderedDict[_KT | _T1, _VT | _T2]: ...  # type: ignore[misc]
+        def __ror__(self, value: dict[_KT2, _T], /) -> OrderedDict[_KT | _KT2, _VT | _T]: ...  # type: ignore[misc]
 
 @disjoint_base
 class defaultdict(dict[_KT, _VT]):
@@ -488,12 +493,12 @@ class defaultdict(dict[_KT, _VT]):
     @overload  # type: ignore[override]
     def __or__(self, value: dict[_KT, _VT], /) -> Self: ...
     @overload
-    def __or__(self, value: dict[_T1, _T2], /) -> defaultdict[_KT | _T1, _VT | _T2]: ...
+    def __or__(self, value: dict[_KT2, _T], /) -> defaultdict[_KT | _KT2, _VT | _T]: ...
 
     @overload  # type: ignore[override]
     def __ror__(self, value: dict[_KT, _VT], /) -> Self: ...
     @overload
-    def __ror__(self, value: dict[_T1, _T2], /) -> defaultdict[_KT | _T1, _VT | _T2]: ...  # type: ignore[misc]
+    def __ror__(self, value: dict[_KT2, _T], /) -> defaultdict[_KT | _KT2, _VT | _T]: ...  # type: ignore[misc]
 
 class ChainMap(MutableMapping[_KT, _VT]):
     maps: list[MutableMapping[_KT, _VT]]
@@ -538,29 +543,29 @@ class ChainMap(MutableMapping[_KT, _VT]):
     if sys.version_info >= (3, 13):
         @classmethod
         @overload
-        def fromkeys(cls, iterable: Iterable[_T], /) -> ChainMap[_T, Any | None]: ...
+        def fromkeys(cls, iterable: Iterable[_KT], /) -> ChainMap[_KT, Any | None]: ...
     else:
         @classmethod
         @overload
-        def fromkeys(cls, iterable: Iterable[_T]) -> ChainMap[_T, Any | None]: ...
+        def fromkeys(cls, iterable: Iterable[_KT]) -> ChainMap[_KT, Any | None]: ...
 
     @classmethod
     @overload
     # Special-case None: the user probably wants to add non-None values later.
-    def fromkeys(cls, iterable: Iterable[_T], value: None, /) -> ChainMap[_T, Any | None]: ...
+    def fromkeys(cls, iterable: Iterable[_KT], value: None, /) -> ChainMap[_KT, Any | None]: ...
     @classmethod
     @overload
-    def fromkeys(cls, iterable: Iterable[_T], value: _S, /) -> ChainMap[_T, _S]: ...
+    def fromkeys(cls, iterable: Iterable[_KT], value: _T, /) -> ChainMap[_KT, _T]: ...
 
     @overload
     def __or__(self, other: Mapping[_KT, _VT]) -> Self: ...
     @overload
-    def __or__(self, other: Mapping[_T1, _T2]) -> ChainMap[_KT | _T1, _VT | _T2]: ...
+    def __or__(self, other: Mapping[_KT2, _T]) -> ChainMap[_KT | _KT2, _VT | _T]: ...
 
     @overload
     def __ror__(self, other: Mapping[_KT, _VT]) -> Self: ...
     @overload
-    def __ror__(self, other: Mapping[_T1, _T2]) -> ChainMap[_KT | _T1, _VT | _T2]: ...
+    def __ror__(self, other: Mapping[_KT2, _T]) -> ChainMap[_KT | _KT2, _VT | _T]: ...
 
     # ChainMap.__ior__ should be kept roughly in line with MutableMapping.update()
     @overload  # type: ignore[misc]
diff --git a/stdlib/decimal.pyi b/stdlib/decimal.pyi
index f116603cf0f2..1d94b005979b 100644
--- a/stdlib/decimal.pyi
+++ b/stdlib/decimal.pyi
@@ -191,8 +191,8 @@ class Context:
     Emax: int
     capitals: int
     clamp: int
-    traps: dict[_TrapType, bool]
-    flags: dict[_TrapType, bool]
+    traps: dict[_TrapType, bool]  # type: ignore[type-var]
+    flags: dict[_TrapType, bool]  # type: ignore[type-var]
     def __init__(
         self,
         prec: int | None = None,
@@ -201,8 +201,8 @@ class Context:
         Emax: int | None = None,
         capitals: int | None = None,
         clamp: int | None = None,
-        flags: dict[_TrapType, bool] | Container[_TrapType] | None = None,
-        traps: dict[_TrapType, bool] | Container[_TrapType] | None = None,
+        flags: dict[_TrapType, bool] | Container[_TrapType] | None = None,  # type: ignore[type-var]
+        traps: dict[_TrapType, bool] | Container[_TrapType] | None = None,  # type: ignore[type-var]
     ) -> None: ...
     def __reduce__(self) -> tuple[type[Self], tuple[Any, ...]]: ...
     def clear_flags(self) -> None: ...
diff --git a/stdlib/inspect.pyi b/stdlib/inspect.pyi
index 9bca21ab2dfd..60c469101006 100644
--- a/stdlib/inspect.pyi
+++ b/stdlib/inspect.pyi
@@ -486,7 +486,7 @@ class BoundArguments:
 _ClassTreeItem: TypeAlias = list[tuple[type, ...]] | list[_ClassTreeItem]
 
 def getclasstree(classes: list[type], unique: bool = False) -> _ClassTreeItem: ...
-def walktree(classes: list[type], children: Mapping[type[Any], list[type]], parent: type[Any] | None) -> _ClassTreeItem: ...
+def walktree(classes: list[type], children: Mapping[type[Any], list[type]], parent: type[Any] | None) -> _ClassTreeItem: ...  # type: ignore[type-var]
 
 class Arguments(NamedTuple):
     args: list[str]
diff --git a/stdlib/marshal.pyi b/stdlib/marshal.pyi
index 04cdf05b1934..cd266f536dc0 100644
--- a/stdlib/marshal.pyi
+++ b/stdlib/marshal.pyi
@@ -16,7 +16,7 @@ _Marshallable: TypeAlias = (
     | list[Any]
     | dict[Any, Any]
     | set[Any]
-    | frozenset[_Marshallable]
+    | frozenset[_Marshallable]  # type: ignore[type-var]
     | types.CodeType
     | ReadableBuffer
     # handled in w_object() in marshal.c
diff --git a/stdlib/multiprocessing/managers.pyi b/stdlib/multiprocessing/managers.pyi
index 0f1d4e87b0dc..b6c84aa7c7f2 100644
--- a/stdlib/multiprocessing/managers.pyi
+++ b/stdlib/multiprocessing/managers.pyi
@@ -183,7 +183,7 @@ if sys.version_info >= (3, 14):
         def __iand__(self, value: AbstractSet[object], /) -> Self: ...
         def __or__(self, value: AbstractSet[_S], /) -> set[_T | _S]: ...
         def __ior__(self, value: AbstractSet[_T], /) -> Self: ...  # type: ignore[override,misc]
-        def __sub__(self, value: AbstractSet[_T | None], /) -> set[_T]: ...
+        def __sub__(self, value: AbstractSet[_T | None], /) -> set[_T]: ...  # type: ignore[override]
         def __isub__(self, value: AbstractSet[object], /) -> Self: ...
         def __xor__(self, value: AbstractSet[_S], /) -> set[_T | _S]: ...
         def __ixor__(self, value: AbstractSet[_T], /) -> Self: ...  # type: ignore[override,misc]
diff --git a/stdlib/selectors.pyi b/stdlib/selectors.pyi
index 4a3478a67552..62db2eb0a52a 100644
--- a/stdlib/selectors.pyi
+++ b/stdlib/selectors.pyi
@@ -25,7 +25,7 @@ class BaseSelector(metaclass=ABCMeta):
     def close(self) -> None: ...
     def get_key(self, fileobj: FileDescriptorLike) -> SelectorKey: ...
     @abstractmethod
-    def get_map(self) -> Mapping[FileDescriptorLike, SelectorKey]: ...
+    def get_map(self) -> Mapping[FileDescriptorLike, SelectorKey]: ...  # type: ignore[type-var]
     def __enter__(self) -> Self: ...
     def __exit__(self, *args: Unused) -> None: ...
 
@@ -33,7 +33,7 @@ class _BaseSelectorImpl(BaseSelector, metaclass=ABCMeta):
     def register(self, fileobj: FileDescriptorLike, events: int, data: Any = None) -> SelectorKey: ...
     def unregister(self, fileobj: FileDescriptorLike) -> SelectorKey: ...
     def modify(self, fileobj: FileDescriptorLike, events: int, data: Any = None) -> SelectorKey: ...
-    def get_map(self) -> Mapping[FileDescriptorLike, SelectorKey]: ...
+    def get_map(self) -> Mapping[FileDescriptorLike, SelectorKey]: ...  # type: ignore[type-var]
 
 class SelectSelector(_BaseSelectorImpl):
     def select(self, timeout: float | None = None) -> list[tuple[SelectorKey, int]]: ...
diff --git a/stdlib/types.pyi b/stdlib/types.pyi
index 39aaa7e9685f..60ea03cdec62 100644
--- a/stdlib/types.pyi
+++ b/stdlib/types.pyi
@@ -7,6 +7,7 @@ from collections.abc import (
     Callable,
     Coroutine,
     Generator,
+    Hashable,
     ItemsView,
     Iterable,
     Iterator,
@@ -70,8 +71,9 @@ if sys.version_info >= (3, 15):
 
 _T1 = TypeVar("_T1")
 _T2 = TypeVar("_T2")
-_KT_co = TypeVar("_KT_co", covariant=True)
+_KT_co = TypeVar("_KT_co", bound=Hashable, covariant=True)
 _VT_co = TypeVar("_VT_co", covariant=True)
+_KT2 = TypeVar("_KT2", bound=Hashable)
 
 # Make sure this class definition stays roughly in line with `builtins.function`
 @final
@@ -289,8 +291,8 @@ class MappingProxyType(Mapping[_KT_co, _VT_co]):  # type: ignore[type-var]  # py
 
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
     def __reversed__(self) -> Iterator[_KT_co]: ...
-    def __or__(self, value: Mapping[_T1, _T2], /) -> dict[_KT_co | _T1, _VT_co | _T2]: ...
-    def __ror__(self, value: Mapping[_T1, _T2], /) -> dict[_KT_co | _T1, _VT_co | _T2]: ...
+    def __or__(self, value: Mapping[_KT2, _T1], /) -> dict[_KT_co | _KT2, _VT_co | _T1]: ...
+    def __ror__(self, value: Mapping[_KT2, _T1], /) -> dict[_KT_co | _KT2, _VT_co | _T1]: ...
 
 if sys.version_info >= (3, 12):
     @disjoint_base
diff --git a/stdlib/typing.pyi b/stdlib/typing.pyi
index 198dd45feedf..91fe70970f00 100644
--- a/stdlib/typing.pyi
+++ b/stdlib/typing.pyi
@@ -411,10 +411,10 @@ _FT = TypeVar("_FT", bound=Callable[..., Any] | type)
 
 # These type variables are used by the container types.
 _S = TypeVar("_S")
-_KT = TypeVar("_KT")  # Key type.
+_KT = TypeVar("_KT", bound=Hashable)  # Key type.
 _VT = TypeVar("_VT")  # Value type.
 _T_co = TypeVar("_T_co", covariant=True)  # Any type covariant containers.
-_KT_co = TypeVar("_KT_co", covariant=True)  # Key type covariant containers.
+_KT_co = TypeVar("_KT_co", bound=Hashable, covariant=True)  # Key type covariant containers.
 _VT_co = TypeVar("_VT_co", covariant=True)  # Value type covariant containers.
 _TC = TypeVar("_TC", bound=type[object])
 
@@ -729,37 +729,37 @@ class MutableSequence(Sequence[_T]):
     def remove(self, value: _T, /) -> None: ...
     def __iadd__(self, values: Iterable[_T], /) -> typing_extensions.Self: ...
 
-class AbstractSet(Collection[_T_co]):
+class AbstractSet(Collection[_KT_co]):
     @abstractmethod
     def __contains__(self, x: object, /) -> bool: ...
     def _hash(self) -> int: ...
     # Mixin methods
     @classmethod
-    def _from_iterable(cls, it: Iterable[_S], /) -> AbstractSet[_S]: ...
-    def __le__(self, other: AbstractSet[Any], /) -> bool: ...
-    def __lt__(self, other: AbstractSet[Any], /) -> bool: ...
-    def __gt__(self, other: AbstractSet[Any], /) -> bool: ...
-    def __ge__(self, other: AbstractSet[Any], /) -> bool: ...
-    def __and__(self, other: AbstractSet[Any], /) -> AbstractSet[_T_co]: ...
-    def __or__(self, other: AbstractSet[_T], /) -> AbstractSet[_T_co | _T]: ...
-    def __sub__(self, other: AbstractSet[Any], /) -> AbstractSet[_T_co]: ...
-    def __xor__(self, other: AbstractSet[_T], /) -> AbstractSet[_T_co | _T]: ...
+    def _from_iterable(cls, it: Iterable[_KT_co], /) -> AbstractSet[_KT_co]: ...
+    def __le__(self, other: AbstractSet[Hashable], /) -> bool: ...
+    def __lt__(self, other: AbstractSet[Hashable], /) -> bool: ...
+    def __gt__(self, other: AbstractSet[Hashable], /) -> bool: ...
+    def __ge__(self, other: AbstractSet[Hashable], /) -> bool: ...
+    def __and__(self, other: AbstractSet[Hashable], /) -> AbstractSet[_KT_co]: ...
+    def __or__(self, other: AbstractSet[_KT], /) -> AbstractSet[_KT_co | _KT]: ...
+    def __sub__(self, other: AbstractSet[Hashable], /) -> AbstractSet[_KT_co]: ...
+    def __xor__(self, other: AbstractSet[_KT], /) -> AbstractSet[_KT_co | _KT]: ...
     def __eq__(self, other: object, /) -> bool: ...
-    def isdisjoint(self, other: Iterable[Any], /) -> bool: ...
+    def isdisjoint(self, other: Iterable[Hashable], /) -> bool: ...
 
-class MutableSet(AbstractSet[_T]):
+class MutableSet(AbstractSet[_KT]):
     @abstractmethod
-    def add(self, value: _T, /) -> None: ...
+    def add(self, value: _KT, /) -> None: ...
     @abstractmethod
-    def discard(self, value: _T, /) -> None: ...
+    def discard(self, value: _KT, /) -> None: ...
     # Mixin methods
     def clear(self) -> None: ...
-    def pop(self) -> _T: ...
-    def remove(self, value: _T, /) -> None: ...
-    def __ior__(self, it: AbstractSet[_T], /) -> typing_extensions.Self: ...  # type: ignore[override,misc]
-    def __iand__(self, it: AbstractSet[Any], /) -> typing_extensions.Self: ...
-    def __ixor__(self, it: AbstractSet[_T], /) -> typing_extensions.Self: ...  # type: ignore[override,misc]
-    def __isub__(self, it: AbstractSet[Any], /) -> typing_extensions.Self: ...
+    def pop(self) -> _KT: ...
+    def remove(self, value: _KT, /) -> None: ...
+    def __ior__(self, it: AbstractSet[_KT], /) -> typing_extensions.Self: ...  # type: ignore[override,misc]
+    def __iand__(self, it: AbstractSet[Hashable], /) -> typing_extensions.Self: ...
+    def __ixor__(self, it: AbstractSet[_KT], /) -> typing_extensions.Self: ...  # type: ignore[override,misc]
+    def __isub__(self, it: AbstractSet[Hashable], /) -> typing_extensions.Self: ...
 
 class MappingView(Sized):
     __slots__ = ("_mapping",)
diff --git a/stdlib/weakref.pyi b/stdlib/weakref.pyi
index e81052de7d26..c2c76b59cdfe 100644
--- a/stdlib/weakref.pyi
+++ b/stdlib/weakref.pyi
@@ -1,7 +1,7 @@
 from _typeshed import SupportsKeysAndGetItem
 from _weakref import getweakrefcount as getweakrefcount, getweakrefs as getweakrefs, proxy as proxy
 from _weakrefset import WeakSet as WeakSet
-from collections.abc import Callable, Iterable, Iterator, Mapping, MutableMapping
+from collections.abc import Callable, Hashable, Iterable, Iterator, Mapping, MutableMapping
 from types import GenericAlias
 from typing import Any, ClassVar, Generic, ParamSpec, TypeVar, final, overload
 from typing_extensions import Self, disjoint_base
@@ -25,7 +25,7 @@ __all__ = [
 _T = TypeVar("_T")
 _T1 = TypeVar("_T1")
 _T2 = TypeVar("_T2")
-_KT = TypeVar("_KT")
+_KT = TypeVar("_KT", bound=Hashable)
 _VT = TypeVar("_VT")
 _CallableT = TypeVar("_CallableT", bound=Callable[..., Any])
 _P = ParamSpec("_P")
@@ -58,7 +58,7 @@ class ReferenceType(Generic[_T]):  # "weakref"
     def __new__(cls, o: _T, callback: Callable[[Self], Any] | None = ..., /) -> Self: ...
     def __call__(self) -> _T | None: ...
     def __eq__(self, value: object, /) -> bool: ...
-    def __hash__(self) -> int: ...
+    def __hash__(self: ReferenceType[Hashable]) -> int: ...
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
 
 ref = ReferenceType
diff --git a/stdlib/xmlrpc/client.pyi b/stdlib/xmlrpc/client.pyi
index 3107f1cbb377..df5c3fa447b6 100644
--- a/stdlib/xmlrpc/client.pyi
+++ b/stdlib/xmlrpc/client.pyi
@@ -111,7 +111,7 @@ class ExpatParser:  # undocumented
 _WriteCallback: TypeAlias = Callable[[str], object]
 
 class Marshaller:
-    dispatch: dict[type[_Marshallable] | Literal["_arbitrary_instance"], Callable[[Marshaller, Any, _WriteCallback], None]]
+    dispatch: dict[type[_Marshallable] | Literal["_arbitrary_instance"], Callable[[Marshaller, Any, _WriteCallback], None]]  # type: ignore[type-var]
     memo: dict[Any, None]
     data: None
     encoding: str | None
diff --git a/stubs/dateparser/dateparser/languages/locale.pyi b/stubs/dateparser/dateparser/languages/locale.pyi
index 587414f06bfe..1deb2b84440b 100644
--- a/stubs/dateparser/dateparser/languages/locale.pyi
+++ b/stubs/dateparser/dateparser/languages/locale.pyi
@@ -24,7 +24,7 @@ class Locale:
     ) -> bool: ...
     def count_applicability(self, text: str, strip_timezone: bool = False, settings: Settings | None = None) -> list[int]: ...
     @staticmethod
-    def clean_dictionary(dictionary: Mapping[_K, _V], threshold: int = 2) -> Mapping[_K, _V]: ...
+    def clean_dictionary(dictionary: Mapping[_K, _V], threshold: int = 2) -> Mapping[_K, _V]: ...  # type: ignore[type-var]
     def translate(
         self,
         date_string: str,
diff --git a/stubs/gevent/gevent/selectors.pyi b/stubs/gevent/gevent/selectors.pyi
index 12614ef1e6ff..432af20dc4e2 100644
--- a/stubs/gevent/gevent/selectors.pyi
+++ b/stubs/gevent/gevent/selectors.pyi
@@ -19,6 +19,6 @@ class GeventSelector(BaseSelector):
     def unregister(self, fileobj: FileDescriptorLike) -> SelectorKey: ...
     def select(self, timeout: float | None = None) -> list[tuple[SelectorKey, int]]: ...
     def close(self) -> None: ...
-    def get_map(self) -> Mapping[FileDescriptorLike, SelectorKey]: ...
+    def get_map(self) -> Mapping[FileDescriptorLike, SelectorKey]: ...  # type: ignore[type-var]
 
 DefaultSelector = GeventSelector
diff --git a/stubs/requests-oauthlib/requests_oauthlib/oauth2_session.pyi b/stubs/requests-oauthlib/requests_oauthlib/oauth2_session.pyi
index 911045dcdf8d..6d2e126a3cdb 100644
--- a/stubs/requests-oauthlib/requests_oauthlib/oauth2_session.pyi
+++ b/stubs/requests-oauthlib/requests_oauthlib/oauth2_session.pyi
@@ -12,14 +12,17 @@ _Token: TypeAlias = dict[str, Incomplete]  # oauthlib.oauth2.Client.token
 @type_check_only
 class _AccessTokenResponseHook(Protocol):
     def __call__(self, response: requests.Response, /) -> requests.Response: ...
+    def __hash__(self) -> int: ...
 
 @type_check_only
 class _RefreshTokenResponseHook(Protocol):
     def __call__(self, response: requests.Response, /) -> requests.Response: ...
+    def __hash__(self) -> int: ...
 
 @type_check_only
 class _ProtectedRequestHook(Protocol):
     def __call__(self, url, headers, data, /) -> tuple[Incomplete, Incomplete, Incomplete]: ...
+    def __hash__(self) -> int: ...
 
 @type_check_only
 class _ComplianceHooks(TypedDict):