If you loved An American Tail: The Mystery of the Night Monster, try An American Tail: The Treasure of Manhattan Island
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

An American Tail: The Mystery of the Night Monster
→
Try this next

An American Tail: The Treasure of Manhattan Island
What they share
Both films are directed by Larry Latham, and they both carry the cozy, playful mood tags, and they sit in Adventure / Animation / Family territory. If that's the register that drew you to An American Tail: The Mystery of the Night Monster, the second film will land in a comparable space — through a different lens.
cozyplayful
What An American Tail: The Treasure of Manhattan Island is
Fievel digs up more than he bargained for. He finds a map that supposedly leads to treasure under Old New York. His quest yields unexpected cultural enlightenment.