All alternate attires are unlocked through 2K Showcase mode by completing all objectives for the event that the attire is worn.

Alberto Del Rio SummerSlam '11
Big Show RAW Aug 13 '12
Big Show SummerSlam '12
Chris Jericho '02 Survivor Series '02
CM Punk '11-'12 Hell in a Celll '11
CM Punk '11-'12 Night of Champions '11
CM Punk '11-'12 RAW Jul 16 '12
CM Punk '11-'12 RAW Jul 23 '12
CM Punk '11-'12 SummerSlam '11
CM Punk '11-'12 SummerSlam '12
CM Punk '11-'12 Survivor Series '11
CM Punk '12-'13 Elimination Chamber '13
CM Punk '12-'13 Hell in a Cell '12
CM Punk '12-'13 Night of Champions '12
CM Punk '12-'13 RAW Feb 25 '13
CM Punk '12-'13 RAW Nov 12 '12
CM Punk '12-'13 Royal Rumble '13
CM Punk '12-'13 Survivor Series '12
John Cena Money in the Bank '11
John Cena RAW Jul 15 '12
John Cena Survivor Series '12
Rey Mysterio RAW Jul 25 '11
Rob Van Dam RAW Dec 2 '02
Rob Van Dam RAW Nov 25 '02
Rob Van Dam Survivor Series '02
Ryback Hell in a Cell '12
Ryback Survivor Series '12
Shawn Michaels Armageddon '02
Shawn Michaels Bad Blood '04
Shawn Michaels RAW '03
Shawn Michaels Royal Rumble '04
Triple H Armageddon '02
Triple H Backlash '03
Triple H Bad Blood '04
Triple H Night of Champions '11
Triple H RAW Oct 28 '02
Triple H SummerSlam '02