This some of the extra content you can unlock under certain conditions to use for your Home Avatar in Playstation Home.

Unlockable	How to Unlock
"Winner!" T-Shirt	Get the "Tenpeat" Trophy.
Fight T-Shirt	Get the Rival Schooled Trophy.
The Super SFIV "TressPass" T-shirt	After you Win The "Herculean Effort" Trophy your able to attain the T-shirt.
K.O. T-shirt	Get the "Sunspotter" Trophy (Amigo, perform 365 Super or Ultra Combo finishes against your opponents! The dawn is coming!)