WoW Transmog — Browse All Transmog Sets
Browse all 3,100+ World of Warcraft transmog appearance sets. Filter by expansion, armor type (Cloth, Leather, Mail, Plate, Cosmetic), and PvP sets. Track your wardrobe completion across all expansions.
Browse transmog sets from raids, dungeons, PvP, and quests across all expansions. Filter by armor type (plate, mail, leather, cloth) and source. Track which appearances you own and which you still need via Battle.net sync.
Arathi Abbot's Armor
Cloth set. The War Within. I believe one must also have one of the trinkets equipped to receive the equip buff.
Arathi Abbot's Armor is a transmog set obtained by opening 
Arathi Champion's Spoils from Raen Dawncavalyr in Hallowfall.
Visit Raen Dawncavalyr
Find Raen Dawncavalyr at 28.2, 56.0 in Hallowfall and open Arathi Champion's Spoils to receive armor pieces for your class.
Tips
Each Arathi Champion's Spoils grants a non-duplicate piece of Arathi armor that your character class can equip, until you collect all available pieces for your armor type.
After obtaining all pieces for your class, subsequent openings may award duplicate pieces or items from other armor or weapon classes.
As of patch 11.2, these boxes reward Adventurer track items rather than the previously upgraded Veteran track rewards.