Related Meta keeps 'block' lists of ex-employees – and even a VP can't get you off them (43 points, 17 days ago, 20 comments) https://news.ycombinator.com/item?id=43280435
I understand many do not always have a choice, but if one did, why would they ever willing go back to a former employer?
Every organisation does, whether it's a formal list or not.
Government agencies have stricter requirements than private companies when it comes to flagging people as not-for-rehire, but not even they will welcome you back if you get fired for cause.