The Harvest Festival is a small celebration held in honor of the fallen heroes of the Horde and Alliance. This holiday is based on real-world harvest festivals such as Korea’s Chuseok and the Chinese Mid-Autumn Festival.
Small feast tables have been set up outside of Orgrimmar and Ironforge from which players can sample various harvest foods, and a nearby quest giver presents the task of honoring a fallen hero. Horde players will be sent to leave an object of tribute at the monument to Grom Hellscream in Ashenvale while Alliance players are sent to the tomb of Uther the Lightbringer in the Western Plaguelands. New to 2015, players can get Anxious Spiritshard, Forlorn Spiritshard, Peaceful Spiritshard, or Vengeful Spiritshard.
There are no special player titles associated with this event.
More information on Wowhead.