Reincarnation AU: In which stories with historical canon setting have the characters become reincarnated into a modern setting and in doing so they are quite similar to their canon selves. Other times the characters or just one of them is reincarnated into another world, which they may or may not retrain their memories from their previous life.
Reverse AU: Is when the roles (and sometimes backstories) of the characters are swapped, such as the hero is the villain and the villain is the hero.
Rockstar AU: In which the main casts is a popular music band or one of them is a solo artists with many groupies which may consist the rest of the characters.
Roommate AU: In which the characters in a fandom are all living together in an apartment or an house. Usually this kind of story is focused on two characters that become roommates.
Royalty AU: Where one or more characters (who canonically aren't) are members of a royal family. This usually goes hand in hand with a historical period, featuring a Medieval AU or Regency AU, although some works are set in Modern times or even the Future.
YOU ARE READING
The AU Dictionary
De TodoA book explaining all of the different AU's. None of these belong to me. I got this from a blog I saw.