Give me a list of great sci-fi
Sci-fi movies can be graded by many different dimensions to determine "the best".  The largest universe market cap for a sci fi universe is Star Wars created by George Lucas and all its canon. Star Wars at its core story is about an all binding energy called the force which bound the galaxy together which a few people could harness its power.  Its a classic story of good vs evil paired with amazing special effects to give the viewer an immersive believable universe.  One of the longest running Sci Fi Series with a cult following was Stargate SG-1 which aired for 10 seasons and had two movies created.    Stargate SG-1 is about a network of inter-planetary gates that allowed for anyone to instantaneously travel between entire different planets.  The saga is ripe with discovering new cultures in foreign planets, intermixed with long story arcs about formidable foes and a team with a very diverse set of people and aliens battling for good of the galaxy.  Stargate SG-1 had amazing character development over its 10 season course which made it a great fan favorite.  The 2004 remake of Battlestar Galactica is an epic story of artificial intelligence versus humanity.  Humanity is being hunted and on the brink of all out extinction.  Its a war-time classic that explores the factors that make us human, what a society is about, and survival.