We talk a lot about great movies that never should’ve been franchises. But what standalone movie has worked surprisingly great as a franchise?

There’s a lot of great movies out there with terrible unnecessary sequels (The Hangover, Jaws, Matrix, Terminator, etc). But what standalone movies whose stories were good enough on their own, become surprisingly great series? Specifically, movies where audiences didn’t demand a sequel, but one worked out surprisingly well and wound up launching a cultural staple?

There’s stuff like Star Wars and Shrek, but I guess those were popular enough that sequel demand was inevitable. But in terms of sequels that were dismissed as unnecessary and lame cash-grabs, what comes to mind as a surprise? I suppose Top Gun: Maverick and Puss in Boots 2 come to mind, as well as the BTTF sequels.