2. supernatural
2a. ghosts/entities
2b. monsters
2c. biblical beings
2d. rules/games

3. Sci-Fi horror
3a. aliens/extraterrestrial
3b. artificial intelligence/droids
3c. scientific expenditures/experiments
3d. existential horror

4. post-apocalyptic
4a. zombie apocalypse/plague
4b. nuclear fallout
4c. environmental disaster