Collected here are some movies that for all intents and purposes, really didn't require a sequel (or in a few cases, a prequel) to be made. And yet they got one anyway, sometimes a really long time after the original film. Presented here are the original film and the sequel, meaning the first sequel only. Now just to be clear, some of the sequels are actually good, even excellent films (like Blade Runner 2049), but the prior film (which in some cases may be a sequel itself) worked so well as a standalone or as an end point to a series, that the follow-up film didn't really need to be made. And sometimes the first film was so poor it is hard to believe anyone thought it a good idea to make another (and in some cases then another and another).
I will have seen the original films in this list, but not necessarily all the sequels, many being a 'why bother?' situation for me.