Here is the full list of all 50 Injustice: Gods Among Us Ultimate Edition achievements.
Defeat every Villain With Batman
Win a match as Deathstroke without missing a shot (minimum 12 shots)
Cause maximum damage in all Arenas (does not include Practice mode)
Win a match with Green Arrow using only arrows
Win a single online match
Perform 8 throws and win in a multiplayer match
Use every interactable and win in a multiplayer match
Win a multiplayer match with a timeout
Win all story mode minigames
Dethrone the King in an online match
Win 1 complete Ranked match
Enter Online Practice with someone on your friends list
Complete Tutorial
Knock opponent through all transitions across all levels
Unlock everything in the Archives
Enter Practice Mode
Get 3 stars on 1 S.T.A.R. Lab Mission
Complete 1 S.T.A.R. Lab Mission
Complete Classic Battle with any character
Complete 100% of Story Mode
Knock an opponent through a transition
Complete 50% of Story Mode
Win a match with the super move of any character
Unlock a costume in the Archives
Unlock All costumes in the Archives
Equip a new Background Image
Win a Clash sequence with any character
Reach Level 10
Equip a new Icon
Equip a new Character Portrait
View Your Hero Card
Complete Classic Battle with all characters
Complete Battle Mode
Beat All S.T.A.R. Lab Missions (Excluding DLC)
Reach Level 100
Vote Correctly in a KOTH match
Defeat a Survivor
Win 100 complete Online Matches
Play 200 complete Online Matches
Win 10 complete Ranked matches
Get 100 Stars in S.T.A.R. Lab Mode
Complete All S.T.A.R. Lab Missions with 3 Stars
Perform a 10 hit combo with every character
Perform every character's supermove
Perform every special move of every character
Perform every Meter Burn special move of every character
Win with Batman using every special move and his Supermove
Perform every level interaction once
Make a comeback when at low health (10% or less)
Send an opponent through all three Metropolis transitions in one fight