Bonus offline accessories - Become the champion of two weight divisions in Legacy mode, then reach "G.O.A.T" status to unlock extra offline accessories.

Bonus online accessories - Win the Lightweight, Middleweight, and Heavyweight Online belts to unlock extra online accessories.

Easy "David And Goliath", "King Of The Rope-A-Dope", and "My Style Is Impetuous" trophies - Set the round time to 1 minute and the rounds to 1. Just punch him enough to win by decision.

Maximum stats in Legacy mode - Start a new legacy. Win the tourney, then go to punch totals in the last fight. Press Circle to get +5 to Power, Stamina, and Heart again. Repeat this until your stats are at maximum.

Trophies - Successfully complete one of the following tasks to get a trophy:

A Force To Reckon With (Silver): Win 10 online ranked matches.
Comeback Kid (Silver): Win a online ranked match after being knocked down twice.
David And Goliath (Gold): Beat CPU Mike Tyson in fight now on G.O.A.T.
Echo Trunk Challenge (Silver): Beat CPU Miguel Cotto in fight now on pro.
Get In The Ring (Bronze): Win a fight now match against the CPU.
GOAT (Gold): Retire as the greatest of all time.
King Of The Rope-a-dope (Gold): Beat CPU Mohammad Ali in fight now on G.O.A.T.
Knock A Sucker Out (Silver): Win by a knockout in a fight now match against the CPU.
L (Gold): Win the lightweight championship belt in online world championship mode.
Man Up Manny (Silver): Beat CPU Manny Paqcquiao in fight now on champion.
My Style Is Impetuous (Gold): Beat CPU Mike Tyson on G.O.A.T. using a created boxer in Fight Now.
New Blood (Bronze): Import a boxer into Legacy mode.
Pain Brings Glory (Bronze): Win a match in online world championship mode.
Platinum Trophy: Unlock all other trophies.
Solid Contender (Silver): Win 5 online ranked matches.
The Champ Is Here (Gold): Win a championship belt in a single weight class.
The Road Is Long (Silver): Win 10 fights in Legacy mode.
Undefeated (Silver): Win 5 consecutive Legacy mode fights.
Walk Like 10 Men (Silver): Win 10 fight now matches against the CPU.
XL (Gold): Win the middleweight championship belt in online world championship mode.
XXL (Gold): Win the heavyweight championship belt in online world championship mode.

Additionally, there is one secret trophy:

You're In The Game (Bronze): Create a boxer using the photo game face tool.