Star Wars stories, such as books, comics, the movies or TV shows (both canon and non); books in general; I have about 40 Top Gear magazines, does that count?
Though, I don't exactly consider myself a "collector", just a massive fan of certain franchises, and the same goes for Pokémon!
Recently I've been trying to jump into deeper anime, so, I've started collecting Studio Ghibli films (started with Princess Mononoke, Spirited Away and My Neighbour Totoro).