1. ricstar -- this community, for a very tiny sub-section of fandom, is super awesome! It's more like an X-Factor community, though has an obvious focus on Rictor and Shatterstar (the OTP of my life). You get issue summaries/reviews, discussions about issues, scans, fanmixes, fanfic, fanart, news about the creators, etc. Everyone is really friendly, encouraging and chatty.
2. castlegloria -- another tiny fandom community for the manga From Eroica With Love. It's actually still pretty active (in the context of a tiny fandom). Stories, discussions, updates about the creator, art, etc. I, by chance, you've never read in the From Eroica With Love fandom, consider giving it a try either in this comm or on AO3 -- Dorian and Klaus are brilliant together.
3. yuletide -- yuletide is so much fun, that I encourage everyone to give it a try. It's huge, yes, but there's a space for everyone. And you might get totally lucky and receive all the Daken stories in the world or the sexiest Hank/Jake story on the planet! I literally love writing for other people, and this is really the only fic exchange that applies to my fandoms (the majority of which are small).