These four which drop a dragon customization:
https://www.wowhead.com/item=197016/cliffside-wylderdrake-maned-tail
I read only certain rares are up each day, at least during beta it was that way, and those select would respawn relatively quickly.
They’re not badass enough and don’t drop a mount so I won’t expect them to appear in the group finder. But I really want that maned tail!