Lunar Festival Harbingers are level 55 quest givers located at the Lunar Pools in Darnassus, Ironforge, Stormwind, Orgrimmar, Thunder Bluff and Undercity.
They are only available during the annual Lunar Festival event.
They start the following quests:
[70] Lunar Fireworks (Lunar Festival)- [70] Valadar Starsong (Lunar Festival)
See List of Darnassus NPCs, List of Ironforge NPCs, List of Stormwind NPCs, List of Orgrimmar NPCs, List of Thunder Bluff NPCs, & List of Undercity NPCs.