I'd be interested in reading more of a specific type of crossover (I've already read the fanfics on it that are out there; there are not that many of them). And that would be Danny Phantom with <insert American crime/cop show here> (my fave being Criminal Minds, but I'm open to CSI, Person of Interest, L&O:SVU, NCIS, Castle, even The Mentalist... oh, and not entirely that genre, but House MD is fun sometimes too).
But, aside from that, I'm content with the series I'm currently into and the amount of fan-response to them. Hmm, unless maybe more of the Smoke Trilogy (book series).
There were some series that I was really into a couple years ago that didn't have much of a discussion on them anywhere (like Kimi no Knife, or Alive: The Final Evolution)... but, while I still like those series, I'm not in that state of "need to find other fans who are into this" anymore (not ruling out that my interest could spike again, 'cause that's happened before, like with my current re-interest in Danny Phantom).
Oh, though not fanfic, I wouldn't mind finding some Shounen Hollywood amv's. As far as my search has brought me, no amv for it currently exists.