Druid sets
A druid set refers to a collection of equipment with a druid class restriction that provides an additional bonus when worn together.
Blizzard so far has only created one full armor set for the complete of Challenge Mode Dungeons; as they've only existed since Mists of Pandaria. In Warlord's of Draenor, achieving a rating of "Gold" in every Challenge Mode dungeon unlocks weapon transmog items.
These 'sets' do not have a proper name and offer no set bonuses. They do however present a unified look and carry druid-friendly stats.