Here is the full list of all 12 Rock Band Metal Track Pack trophies - there are 5 bronze and 7 silver.
Complete Band Tour on Medium difficulty or greater
Complete "Transmaniacon MC" as a full band, with all band members on Hard or Expert
Complete "Killed by Death" on Expert without a band member failing
Get 4 stars or better playing "3s and 7s" with a full band
Play "D.O.A.", "Laid to Rest," and "Hair of the Dog" in Solo Tour
Hit 100% as a Bassist on "Closer," up-strums only
5-star "Red Devil" as a Vocalist in Solo Tour
Score 100% as a Vocalist playing "Forever"
5-Star "Blinded by Fear" on any instrument... with your eyes closed
Play "Screaming for Vengeance" in a Score Duel
5 star "Master of the Universe" with any instrument on Expert
Finish "Thrasher" as an Expert Drummer