1. Spam
2. CSAM/defending posting CSAM
3. incessant hornyposting on unrelated topics. Not like making a sex joke a couple of times, but a persistent history of pornbrain comments in non-NSFW communities. It’s just annoying.

My blocklist (outside of spam accounts) is like 5-6 people on Lemmy. But it’s definitely larger on other social media sites because there are a cesspool of people doing #2 and 3.