for older movies there's tons of them i tend to like slasher movies though (not into torture films or too much scary ghost/possessed,closet jumpy whatever kind of things (one of the newer slashers i enjoyed was freddy vs jason)
for sci fi horror
mimic i like that series quite a bit (number 2 was crazy)
and species series
Infestation (2009)
They Live (1988)
predator
alien/s ect