Movie 1 Joker and Harley Quinn
Movie 2 Penguin and Catwomen
Movie 3 Two Face and Poison Ivy
Movie 4 Ra's al Ghul and Talia
Movie 5 Riddler and Scarecrow
Movie 6 Mr Freeze and Bane
Movie 7 Manbat and Madhatter
Movie 8 Killercroc and Clayface
Movie 9 Ventriloquist and Scarface
Movie 1: The Joker, Joe Chill, Carmine Falcone and family, Commissioner Loeb, Lieutenant Flass
Movie 2: The Penguin, Catwoman, Rupert Thorne
Movie 3: Two-Face (after Harvey Dent has been set up as an ally/good guy over the previous two films), The Riddler, Salvatore Maroni, Tony Zucco
Spin-off Catwoman Movie: Black Mask, The Mad Hatter, Clayface
Movie 4: Mr. Freeze, Poison Ivy, Dr. Jason Woodrue, Rupert Thorne (released from prison)
Movie 5: Ra's al Ghul, Talia al Ghul, Bane, Lady Shiva
Movie 6: The Joker (in Arkham), The Scarecrow, Harley Quinn, Lew Moxon, Joe Chill (as an old man)
If you've got story ideas for what you would do, how and why would, respectively, the Penguin and Catwoman, Two-Face and the Riddler and Mr. Freeze and Poison Ivy work together?
shareI'd probably split some of those pairs up - we've already had Penguin/Catwoman and Freeze/Bane movies. I'd keep Joker and Harley together. Then go with
Penguin/Clayface
Scarecrow/Bane
Catwoman/Killercroc
Two-Face/Man-Bat
Riddler/Mr Freeze
Poison Ivy/Solomon Grundy (always liked him)
Ra's al Ghul/King Tut!
"A big ball of wibbly wobbly, timey wimey stuff" The Tenth Doctor explains all.