Demons and Haunting
Unlike most horror stories, these two tend to hit home the hardest for most people. Most rational people don’t believe in vampires or werewolves and no matter how scary the movie they watched or the novel they read, there won’t be any lasting anxiety from it. On the other hand, many people have at least an itsy-bitsy piece of their brain that whispers “maybe” when asked if demons, ghosts or similar supernatural beings exist. It’s that uncertainty that leaves people feeling uneasy long after the movie or novel is finished.
I like these kinds of stories because they can get extremely outlandish without losing that “what if” factor. That gives the writers or directors a lot more leeway to make the story as exciting as possible without losing the audience.