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