If you loved Zatch Bell! 101st Devil, try One Piece: Chopper's Kingdom on the Island of Strange Animals
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.

Zatch Bell! 101st Devil

One Piece: Chopper's Kingdom on the Island of Strange Animals
What they share
Both films are directed by Junji Shimizu, and they both carry the playful mood tag, and they sit in Action / Adventure / Animation territory. If that's the register that drew you to Zatch Bell! 101st Devil, the second film will land in a comparable space — through a different lens.
What One Piece: Chopper's Kingdom on the Island of Strange Animals is
You wash ashore in a riot of geysers, landing alone on an island where the animals crown you king. While your crew searches the far shore the horn hunters arrive, bowing to a violinist who chews horns for power and eyes the island’s greatest treasure. The animals taught you something about fear you’re about to teach him.