Successfully complete one of the following tasks to unlock the corrsponding bonus:

Bonus	Task
Bardock	Finish all missions dealing with Bardock in Story mode 2.
Broly	Face Broly three times, then finish the "other" saga in Story mode.
Cell Saga characters and techniques	Successfully complete the Cell Saga in Story mode.
Cooler	Face Cooler three three times, then finish the "other" saga in Story mode.
Fighters Road mode	Successfully compete the "Dragon" mission, then buy the Capsule from the shop.
Frieza Saga characters and techniques	Successfully complete the Frieza Saga in Story mode.
GT Saga characters and techniques	Successfully complete the GT Saga in Story mode.
Janemba	Face Janemba two times, then finish the "other" saga in Story mode.
Majin Buu Saga characters and techniques	Successfully complete the Majin Buu Saga in Story mode.
Pikkon	Defeat Pikkon in Story mode 2.
Saiyan Saga characters and techniques	Successfully complete the Saiyan Saga in Story mode.