Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Giant Pumpers Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Giant Pumpers suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Transmog Sets
Giant Pumpers is part of the transmog set Soul Priest's Raiment (Priest only), which the Appearances collection lists in 3 versions. The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 113903 (113898 to 113908) were usually added in the same batch as Giant Pumpers: the same quest line, zone, vendor or reward set.