diff --git a/stdlib/@tests/stubtest_allowlists/common.txt b/stdlib/@tests/stubtest_allowlists/common.txt
index 13024e94aaf3..66c7de1b3fa7 100644
--- a/stdlib/@tests/stubtest_allowlists/common.txt
+++ b/stdlib/@tests/stubtest_allowlists/common.txt
@@ -430,7 +430,6 @@ inspect.Signature.empty  # set as private marker _empty
 
 # These multiprocessing proxy methods have *args, **kwargs signatures at runtime,
 # But have more precise (accurate) signatures in the stub
-multiprocessing.managers.BaseListProxy.__imul__
 multiprocessing.managers.BaseListProxy.__len__
 multiprocessing.managers.BaseListProxy.__reversed__
 multiprocessing.managers.BaseListProxy.reverse
diff --git a/stdlib/multiprocessing/managers.pyi b/stdlib/multiprocessing/managers.pyi
index c5a1134377a1..3ab7d87f8d6f 100644
--- a/stdlib/multiprocessing/managers.pyi
+++ b/stdlib/multiprocessing/managers.pyi
@@ -2,7 +2,7 @@ import queue
 import sys
 import threading
 from _typeshed import Incomplete, SupportsKeysAndGetItem, SupportsRichComparison, SupportsRichComparisonT
-from collections.abc import Callable, Iterable, Iterator, Mapping, MutableMapping, MutableSequence, Sequence
+from collections.abc import Callable, Iterable, Iterator, Mapping, MutableMapping, Sequence
 from types import TracebackType
 from typing import Any, AnyStr, ClassVar, Generic, SupportsIndex, TypeVar, overload
 from typing_extensions import Self, TypeAlias
@@ -86,10 +86,11 @@ class DictProxy(BaseProxy, MutableMapping[_KT, _VT]):
     if sys.version_info >= (3, 13):
         def __class_getitem__(cls, args: Any, /) -> Any: ...
 
-class BaseListProxy(BaseProxy, MutableSequence[_T]):
+class BaseListProxy(BaseProxy, Generic[_T]):
     __builtins__: ClassVar[dict[str, Any]]
     def __len__(self) -> int: ...
     def __add__(self, x: list[_T], /) -> list[_T]: ...
+    def __contains__(self, value: object, /) -> bool: ...
     def __delitem__(self, i: SupportsIndex | slice, /) -> None: ...
     @overload
     def __getitem__(self, i: SupportsIndex, /) -> _T: ...
@@ -99,6 +100,7 @@ class BaseListProxy(BaseProxy, MutableSequence[_T]):
     def __setitem__(self, i: SupportsIndex, o: _T, /) -> None: ...
     @overload
     def __setitem__(self, s: slice, o: Iterable[_T], /) -> None: ...
+    def __imul__(self, value: SupportsIndex, /) -> Self: ...
     def __mul__(self, n: SupportsIndex, /) -> list[_T]: ...
     def __rmul__(self, n: SupportsIndex, /) -> list[_T]: ...
     def __reversed__(self) -> Iterator[_T]: ...
@@ -109,6 +111,7 @@ class BaseListProxy(BaseProxy, MutableSequence[_T]):
     def count(self, value: _T, /) -> int: ...
     def insert(self, index: SupportsIndex, object: _T, /) -> None: ...
     def remove(self, value: _T, /) -> None: ...
+    def reverse(self) -> None: ...
     # Use BaseListProxy[SupportsRichComparisonT] for the first overload rather than [SupportsRichComparison]
     # to work around invariance
     @overload
@@ -117,8 +120,8 @@ class BaseListProxy(BaseProxy, MutableSequence[_T]):
     def sort(self, *, key: Callable[[_T], SupportsRichComparison], reverse: bool = ...) -> None: ...
 
 class ListProxy(BaseListProxy[_T]):
-    def __iadd__(self, value: Iterable[_T], /) -> Self: ...  # type: ignore[override]
-    def __imul__(self, value: SupportsIndex, /) -> Self: ...  # type: ignore[override]
+    def __iadd__(self, value: Iterable[_T]) -> Self: ...  # type: ignore[override]
+    def __imul__(self, value: SupportsIndex) -> Self: ...  # type: ignore[override]
     if sys.version_info >= (3, 13):
         def __class_getitem__(cls, args: Any, /) -> Any: ...