Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Frozen-Link Chestguard Compares
Who It Suits
Mail is the armor type Evoker, Hunter and Shaman wear. With Agility or Intellect, Frozen-Link Chestguard suits Beast Mastery, Marksmanship and Survival Hunter; Elemental, Enhancement and Restoration Shaman; Devastation, Preservation and Augmentation Evoker.
Transmog Sets
Frozen-Link Chestguard is part of the transmog set Chains of Nightmare's Embrace (Hunter, Shaman and Evoker only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 142131 (142126 to 142136) were usually added in the same batch as Frozen-Link Chestguard: the same quest line, zone, vendor or reward set.