A lot of the anime-related communities have consolidated over time to the ani.social instance. There are historical reasons for this (largely due to hostility from the ml admins), and if you want a brief history for just the general anime community, I previously wrote a post here.
That being said, the ani.social instance has been growing with new communities being added. Here are the more active ones:
[email protected] -- people mostly post fan art these days, but discussion of anything anime-adjacent (anime/manga/VN/hentai/etc.) is explicitly allowed too. In the past I've posted amusing/interesting stills from shows I was watching, custom image composites, screenshot comics, and things like that.
[email protected] -- "A community for sharing relatable real-life situations depicted in anime."