If you loved Batman Unlimited: Animal Instincts, try Batman Unlimited: Monster Mayhem
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

Batman Unlimited: Animal Instincts
→
Try this next

Batman Unlimited: Monster Mayhem
What they share
Both films are directed by Butch Lukic, and they sit in Action / Animation / Family territory. If that's the register that drew you to Batman Unlimited: Animal Instincts, the second film will land in a comparable space — through a different lens.
What Batman Unlimited: Monster Mayhem is
Here we have a DC animated feature, made for the discerning Halloween completist. The Joker recruits a rogue's gallery of spooky supervillains to help him disable Gotham's tech. It's a distraction for kids who are tired of trick-or-treating.