Well anything except how I got it...
Edited to make the title more clear.
Edit 2: If I like your question, it means it's on the list. If it's not I'll try harder to reply. Also please try to see what others have already been asked. I have to run but I'll check in later.
Edit 3: Due to overwhelming pressure and way more posts than I really thought there would be here is the bulk of the list(no I will not share my damn source!). Some of the less important titles left off intentionally. Bomberman LIVE for example. Concerned a comprehensive list may make my source easy to find in the event that somebody is inclined to look. Maybe I'm paranoid or whatever you want to call me but I don't know what information was sent to what people and I'm not going to be that guy. I included all the major games that I felt people would be most interested in.
Edit 4: http://www.gamespot.com/articles/xbox-one-backwards-compatibility-adds-borderlands-/1100-6430303/ - Confirmation of Borderlands.
Assassins Creed - 1-4, Brotherhood and Revelations
Alan Wake and AW American Nightmare
Alien Hominid
Banjo Kazooie and Tooie
Arkham Asylum and City
Bioshock and BS Infinite
Borderlands
COD 4 and both BO
Castle Crushers
Castelvania
Cloning Clyde
Contra
Crackdown 1/2
Dark Souls
Darksiders 2
Dead Island
Dead Rising
Dead Space
Deadliest Warrior
Deadlight
Defense Grid
Dishonored
Duke Nukem 3D
Earth Defense Force
Fable Anniversary 2, and 3
Fallout 3 and New Vegas
Far Cry 3
Gears 1, 2, and 3
Geometry Wars Evolved
Grand Theft Auto 4
Halo 3, 4, ODST, Reach, and Wars
Harms Way
Hexic HD
Hitman Absolution
Hydro Thunder Hurricane
Injustice
Iron Brigade
Just Cause 2
Kameo
Left For Dead 2
Mass Effect
Metal Gear HD Collection
Mirrors Edge
Motocross Madness
Need For Speed Most Wanted(Sorry I don't know if 2k5 or 2k13. Didn't even know that was a thing until today)
Ninja Gaiden
Oblivion
Pacman
Perfect Dark + Zero
Red Dead Redemption
Resident Evil 5
Shadow Complex
Skate 3
Skyrim
Small Arms
The Orange Box
The Witcher 2
Titan Fall
Tomb Raider
Torchlight
Toy Soldiers + CW
Viva Pinata
When this list turns up mostly accurate I better be a bigger celebrity than Smoggy -blam!-in' Pluto! The hate has been strong on this one and I was just trying to do people a solid. Some people here need to take a chill pill and get a life....
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As long as there's Skyrim Oblivion Far Cry 3 Halo Reach I'm ok