12 transmog appearances and 1 mount, pet or toy drop in The Battle for Mount Hyjal.
Antonidas' Aegis of Rapt ConcentrationShield
Apostle of ArgusTwo-Hand
Bristleblitz StrikerRanged
Cataclysm's EdgeTwo-Hand
Leggings of EternityCloth Legs
Legguards of Endless RagePlate Legs
Mail of Fevered PursuitMail Chest
Midnight ChestguardLeather Chest
Robes of RhoninCloth ChestSavior's GraspPlate Chest
Scepter of PurificationHeld In Off-hand
Tempest of ChaosOne-HandSign in with Battle.net to see which of these appearances and collectibles you already have, and which of your characters can still loot Archimonde this reset.