Personally, I love horror comedy. I find a good one endlessly rewatchable. Cabin in the Woods, Return of the Living Dead, Tucker & Dale, Scream, frigging Killer Klowns from Outer Space! Definitely my favorite.
Otherwise I’m really into paranormal & zombie horror. I think that would make up my top three. Fast > slow zombies.
Generally films where the “good guys” don’t win, but if I had to pick a single genre that’d be cosmic horror. In the Mouth of Madness, Event Horizon, Color out of Space, Annihilation, etc.