I disagree.  Many of these do belong in the stdlib and we don't need a python-ideas bike shedding 300 message thread about something so trivial.

We've been using these internally at Google for years.

Its on my plate to identify which ones to accept and get the most used useful ones in.  With an additional eye to which ones we'd likely use when testing the stdlib itself.

They fit right in with https://docs.python.org/3/library/unittest.mock.html#helpers