If you loved South Park: Imaginationland, try South Park (Not Suitable for Children)
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.
You already loved

South Park: Imaginationland
→
Try this next

South Park (Not Suitable for Children)
What they share
Both films are directed by Trey Parker, and they both carry the playful mood tag, and they sit in Animation / Comedy / TV Movie territory. If that's the register that drew you to South Park: Imaginationland, the second film will land in a comparable space — through a different lens.
playful
What South Park (Not Suitable for Children) is
Apparently someone made a whole movie about cartoon kids. Randy investigates a teacher's OnlyFans page. It's about as subtle as you'd expect.