Here's a constantly updated list of every Injustice: Gods Among Us mod that I've ever made:
Assault on Arkham Killer Frost: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8327
Batjoker: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8290
Star Sapphire Flash: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8243
Klassic Ermac: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8287
Hulk Grundy: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8236
Jonah Hex Lobo (still in BETA): http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8253
Heavenly Green Arrow: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8251
Orange Lantern Flash: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8242
Assault on Arkham Killer Frost: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8327
Batjoker: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8290
Star Sapphire Flash: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8243
Klassic Ermac: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8287
Hulk Grundy: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8236
Jonah Hex Lobo (still in BETA): http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8253
Heavenly Green Arrow: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8251
Orange Lantern Flash: http://www.mksecrets.net/forums/eng/viewtopic.php?f=87&t=8242