If you loved Black Butler: Book of Murder, try Yu Yu Hakusho: The Movie - The Golden Seal
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.

Black Butler: Book of Murder

Yu Yu Hakusho: The Movie - The Golden Seal
What they share
Both films are directed by Noriyuki Abe, and they both carry the foreign gem, playful mood tags, and they sit in Action / Adventure / Animation territory. If that's the register that drew you to Black Butler: Book of Murder, the second film will land in a comparable space — through a different lens.
What Yu Yu Hakusho: The Movie - The Golden Seal is
Here's a film that takes a break from the usual Spirit Detective grind. Koenma is kidnapped while on vacation, and the culprits demand a powerful artifact. Yusuke and Kuwabara, also on vacation, must cut their holidays short to save the day. It's a nice change of scenery, literally and figuratively.