I've probably forgotten most of them since I joined so many when I first got obsessed with anime:
1) Captured Wings
2) Yume No Hana (Zeldi-chan's forum)
3) Cardcaptors Uncensored (but I haven't been on in a while)
4) Daybreak Forums (Quit awhile ago because of a certain member which shall remain nameless)
5) Sue Thomas F.B.Eye Fanfic (haven't been on here in forever; and it's not anime)
6) Anime Pokey.net (Just joined, but I don't like it at all. The people aren't even polite enough to welcome you after you post your introduction
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)
7) Black Halo Inc. (Don't go on nearly enough to give a comment)
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The Otaku (Has beautiful wallpapers)
I think that's about it although I'm probably forgetting some.
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I'll post more if I remember.