Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Despair-Bound Armplates Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Despair-Bound Armplates suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Despair-Bound Armplates is part of the transmog set Bloodforged Battleplate (Warrior, Paladin and Death Knight only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 137431 (137426 to 137436) were usually added in the same batch as Despair-Bound Armplates: the same quest line, zone, vendor or reward set.