Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Manawracker Shoulders Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Manawracker Shoulders suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Transmog Sets
Manawracker Shoulders is part of the transmog set Vestments of the Manasinged (Priest, Mage and Warlock only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 134309 (134304 to 134314) were usually added in the same batch as Manawracker Shoulders: the same quest line, zone, vendor or reward set.