Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Arachnofrost Vest Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Arachnofrost Vest suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Similar Items
The 3 items nearest to Arachnofrost Vest (item level 437) in item level among Armor > Cloth, Chest slot, from item level 400 to 545.
Blizzard numbers items as they are created, so the named items next to ID 221176 (221171 to 221181) were usually added in the same batch as Arachnofrost Vest: the same quest line, zone, vendor or reward set.