'Who Framed Roger Rabbit'
My favorite version of a possible sequel that we heard about for this one was "The Toon Platoon," a movie that would have seen Roger and Baby Herman and the other toons head to Europe to fight WWII. But I would have been happy with a sequel that saw Eddie Valiant and Roger having to solve another crime together if that's what got made. The one thing that I'd say is that Robert Zemeckis was one of two filmmakers who would have to be involved to make a real Roger Rabbit sequel, and without Richard Williams right there alongside him, I would have a hard time accepting any sequel to this one. I'm sure you could make a more technically impassive version of this these days, but you're never going to find animation with more soul, and that's the real reason the original worked.