Read from the World of Warcraft client build files.
How Doomsinger's Guise Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Doomsinger's Guise suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Similar Items
The 10 items nearest to Doomsinger's Guise (item level 13) in item level among Armor > Cloth, Head slot, from item level 19 to 20.
Blizzard numbers items as they are created, so the named items next to ID 240702 (240697 to 240707) were usually added in the same batch as Doomsinger's Guise: the same quest line, zone, vendor or reward set.