Darkness & Sound
Mutated beasts, insects as big as houses or plants that try to eat everyone. Can cross into an Apocalyptic setting if nature is on it's bad hair day.
The working of the human mind and it's side effects is at work in psychological horror. Emotional instability, fear, guilt and sometimes a touch of the supernatural to make sure nothing is certain. Show less and let the players own fears fill in the details.
Mad scientists with experiments that go wrong or aliens that try to eat us all.
Zombies are everywhere in games but in a zombie setting they are the core gameplay element.
Spiritual horror - that delves into ghosts, demons, poltergeists, possessions, hell, life after death, paranormal;
Fantasy horror- that delves into zombies, Frankenstein, vampires, werewolves;
Criminal horror - dealing mainly with killers;