Also the bots that simulated activity by reposting the top posts with their highest upvoted comments from a year ago.
Cross-site/server bans because you posted in a community that the moderators of the one you are trying to post in don't like. Sadly already happening with many servers defederating from each other.
Defederating is fine and I think it's a necessary evil to combat spam and problematic shit which wouldn't even be allowed on Reddit, i.e. jailbait, loli/shota artwork, involuntary/revenge porn, bestiality, rampant hate speech.
The problem is when you have a bot banning you from dozens of subreddits because you posted a single comment or voted on something within a community like /r/kotakuinaction, /r/tumblrinaction, /r/watchredditdie, /r/subredditcancer or anywhere else they deem a "hate subreddit."