Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Thornscar Wristguards Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Thornscar Wristguards suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Thornscar Wristguards 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 134520 (134515 to 134525) were usually added in the same batch as Thornscar Wristguards: the same quest line, zone, vendor or reward set.