Creepy old mansions/castles
cobwebs 
spiders 
rats
disfigurement
foreboding names 
sharp objects 
old lab equipment 
poor lighting
lightning flashes 
thunder
character's paranoia 
organ music 
bottled brains/body parts
poor skin
hidden passages
mountaintop homes
dark forests
screeching background music
darkly colored clothing 
abandoned places 
broken cars/wagons 
frightened/dead animals
candlelight
creaking floorboards 
rickety staircases 
creepy children
stares
fortune tellers
malfunctioning radio/electronics 
no cellphone/telephone service
mist/fog
sudden rain 
graveyards
muddy footprints
creepy clowns
sudden loss/activation of power
torture devices