I'll be listing any RELEASED total conversion mods/up-to-date current rosters here. Please don't send me any PMs for your upcoming projects, I'm checking the downloads section regularly and will add any new mod that is released. All the mods are sorted alphabetically.
Historic NBA Mods
Ultimate NBA 2K Mod Pack - Support Thread - Overwrites Files: No
Includes Ultimate Base Roster (250+ Retro Teams/Updated Current Rosters) and 25 other full season mods spanning 60's, 70's, 80's, 90's, 00's and ABA, Ultimate Base Roster Expansion Teams, 1989-2015 Draft Classes and "Retroless UBR" 2012-2013 roster which is to be used with Association and My Player.
Non-NBA Mods
ACB 2K12 - Support Thread - Overwrites Files: Yes
Spanish Basketball League total conversion.
College Hoops 2K12: Tournament Edition - Support Thread - Overwrites Files: Yes
NCAA total conversion.
Euroleague 2K12 - Support Thread - Overwrites Files: Yes
Euroleague Tournament total conversion.
FIBA 2K12 - Support Thread - Overwrites Files: Yes
Total conversion with both current and retro national basketball teams/olympic squads.
Current NBA Rosters
Albys Realistic Roster - Support Thread - Overwrites Files: No
Popular roster file with the current 2012-2013 season squads.
Summer League 2012 - Support Thread - Overwrites Files: No
Roster file with Summer League 2012 squads/jerseys/courts.
Official 2K Roster - Support Thread - Overwrites Files: No
The last Online Data/Roster update by 2K Sports dated June 27, 2012.
Arcade/Fictional Mods
All Pro Basketball 2K12 - Support Thread - Overwrites Files: No
NBA Stars and Role Players from the Past and Present collide in this generic league. Based on the premise of All Pro Football 2K8, this mod lets you mix and match all the players available in NBA 2K12 to your liking.
Blacktop Revitalization - Support Thread - Overwrites Files: No
This mod revitalizes the crappy Blacktop Mode in NBA 2K12 by adding Legend, Current, and Generic "teams" that categorizes the players by skills.
Hoop it Up 2K12 - Support Thread - Overwrites Files: No
This replaces the players of the NBA with crappy players you might find down at your local gym. Fat guys, max height of 6'7", no last names, and really bad ratings.
Kuroko No Basuke - Support Thread - Overwrites Files: Yes
Total conversion of the famous basketball anime/manga.
NBA 2K Jam - Support Thread - Overwrites Files: No
Total conversion trying to recreate the spirit of NBA Jam games.
NBA Street 2K12 - Support Thread - Overwrites Files: No
Takes the NBA players to the street.
NLSC Roster 2K12 - Support Thread - Overwrites Files: No
NLSC users replacing real players.
Related Downloads
Generic Mod Enabler - Support Thread
Small tool that makes you able to use overwriting files without actually overwriting.