Oh man this is such a good one. This is going to be very hard for me.
Signs
War of Worlds
Pandorum
A Quiet Place
Prometheus
Star Wars, Star Trek, Predator and Alien series I can’t put on this list because I feel like they aren’t stand alone movies. The only one I feel like was a stand alone was Prometheus even though it’s tied to Aliens.
Idk..I might have to update this at a later time. SciFi in general are my favorite movies so there is too much to choose from.