Here is the full list of all 51 Rock Band 2 trophies - there are 38 bronze, 10 silver, 2 gold and 1 platinum.
Wow! You've gotten all the trophies in Rock Band 2
Completed all beats at 100BPM or higher, or half of the beats at 180BPM or higher
Completed all beats at 60BPM or higher, or half of the beats at 140BPM or higher
Completed all fills at 100BPM or higher, or half of the fills at 180BPM or higher
Completed all fills at 60BPM or higher, or half of the fills at 140BPM or higher
Was a savior 3 times during a single song
Finished the Endless Setlist 2 in World Tour on Expert
Finished the Endless Setlist 2 in World Tour on Hard
Beat the Impossible Drum Challenge
Beat the Impossible Vocal Challenge
Beat the Impossible Bass Challenge
Bought over $100,000 worth of items from the Rock Shop
Completed the Endless Setlist 2 without pausing or failing
Finished the Endless Setlist 2 in World Tour on Medium
Beat the Impossible Band Challenge
Earned more than 1,000,000 points in a single song
Achieved an 8x Band Multiplier
Beat the Impossible Guitar Challenge
Completed 25 Challenges on Expert
Played in every venue in the world
Scored a 100% rating as a vocalist on Expert
Joined the Rolling Stone Rock Immortals list
Reached 1,000,000 fans in World Tour
Gained the ability to play around the world
Played a set in Eastern Europe
Maintained deployed Overdrive for 90 seconds.
Beat an instrument-specific challenge while playing another instrument
Defeated the last player that defeated you in either Score Duel or Tug of War
Defeated a player in either Score Duel or Tug of War
Competed in a Battle of the Bands event
Played a set in the United Kingdom
Played a set in Western Europe
Won a Jet in World Tour
Made a music video in World Tour
Completed either 25 Challenges on Hard, or 10 Challenges on Expert
Scored 100% notes hit as a guitarist on Expert
Played a set on the East Coast of North America
Scored 100% notes hit as a drummer on Expert
Won a Bus in World Tour
Played a set in Middle America
Scored 100% notes hit as a bassist, up-strums only, on Expert
100% on a guitar solo on Expert, using only the solo buttons
Made a band logo
Hired a staff member
Deployed Vocal Overdrive 4 times in a single song
Won a Van in World Tour
Gold Starred a song
Played a set on the West Coast of North America
Beat any Impossible Challenge on Expert
Unlock an Impossible Challenge
Completed either 25 Challenges on Medium, 10 Challenges on Hard, or 5 Challenges on Expert