Here is the full list of all 13 Bellator: MMA Onslaught trophies - there are 9 bronze, 3 silver and 1 gold.
Win a Superfight Match
Unlock All Striking Skills
Unlock All Throw Skills
Unlock All Submission Skills
Unlock All Technical Skills
Achieve Maximum Level with a Custom Fighter
Finish Tournament Mode
Get Grade S in a Ranked Match
Win 5 Ranked Matches in a Row
Defeat an Opponent in under 20 Seconds in a Ranked Match
Win a Ranked Match without being Hit by a Standing, Clinch, or Ground Strike
Win a Ranked Match without being Thrown
Win a Ranked Match without being Clinched