The following Bat-Villians get dropped on the Predators planet.
1. The Joker
2. Two Face
3. Black Mask
4. The Riddler
8. Simon Hurt
9. The Ventriloquist
Same scenario as in the movie, they crash in the ship on the planet, carrying there standard gear and weaponry.
Also for the sake of plot convience lets say they've at least agreed to work together long enough to kill the predators or get off planet, so no "Joker backstabs them and kills them all" here.