The most important for me is ruff, especially on personal projects with no CI.
Yelp's secrets scanner is nice. I use texthooks to block smart quotes, I block tabs, bad yaml and JSON syntax, and I use a regex to check that the string "-e " doesn't appear in requirements.txt.
I block git conflict markers and a few other trivial things.
I would use liccheck, but it has issues with detecting conflicts that don't exist in system site packages venvs.
I could see using a SPDX license header checker too.
[1] https://gitlab.com/jjg/cptutils/-/blob/master/bin/status-jso...
You do "checks" before your commits?!?
#mustbenice ;)