Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Monstrosity's Gaze Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Monstrosity's Gaze suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Monstrosity's Gaze is part of the transmog set Dorn Defender Armaments (Warrior, Paladin and Death Knight only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 221047 (221042 to 221052) were usually added in the same batch as Monstrosity's Gaze: the same quest line, zone, vendor or reward set.