Ghosts, Skeletons, Zombies and the like. I love to think about who they were and the context they were buried in. Also how other people might interact with the undead.
I guess my vibe is like, you could be sent on a quest to seal the inner sanctum of a family crypt, but I also think you should meet the cousin of the quest giver who's also there because they're looking for the lost family recipe.