Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Heroes' Dreamwalker Leggings Compares
Who It Suits
Leather is the armor type Demon Hunter, Druid, Monk and Rogue wear. With Agility or Intellect, Heroes' Dreamwalker Leggings suits Assassination, Outlaw and Subtlety Rogue; Brewmaster, Mistweaver and Windwalker Monk; Balance, Feral, Guardian and Restoration Druid; Havoc, Vengeance and Devourer Demon Hunter.
Transmog Sets
Heroes' Dreamwalker Leggings is part of the transmog set Heroes' Dreamwalker Battlegear (Druid only). The other 16 pieces:
Items Numbered Next to Heroes' Dreamwalker Leggings
Blizzard numbers items as they are created, so the named items next to ID 39539 (39533 to 39544) were usually added in the same batch as Heroes' Dreamwalker Leggings: the same quest line, zone, vendor or reward set.