Ghosts and Haunted Houses

Golems, Mummies and Reanimated Stalkers

Vampires and Werewolves

Demonic Possession, Witches and Warlocks

Mythological Monsters

Telekinesis and Mind Control

Small Town Horror

Maniacs and Sociopaths

Technohorror and Medical Horror

Rampant Animals

Psychological Horror

Splatterpunk

Comic Horror

Many libraries carry a book called “Genreflecting” or similar titles. However, it is usually kept behind the desk, so you will have to ask for it, but they should be happy to let you peruse it. It will give you more detailed information about these subgenres with example titles.

Hooked on Horror is also an excellent resource by the same company, but it is less common.