Fanboy in what sense? A forum usage would mean something akin to "showing excessive bias" which I believe I'm largely removed of. Being a fan, imo, means admitting a character's limits and faults, not just the good things.
Or fanboy in a media sense, which would be more akin to "dedicated fan." Then there's a bit too many to list. Doctor Who, Spider-Man, various other comic characters, aspects of the Star Wars U, hunters in World of Warcraft, Nightwish, The Arcade Fire, Modest Mouse, The Beastie Boys, a few others bands, my favorite web comics, Groundhog Day, beer or specific beers, novels and novelists (Joseph Campbell, Jorge Luis Borges, Tolkien, Neil Gaiman, others) etc. etc. etc.