Kinnaras
The Kinnaras are a tribe often spoken of along with the Gandharvas and Yakshas. Puranas mention about an Asura with a horse head, who was known as Hayagrīva (which in Sanskrit means the horse headed one; Haya = horse and grīva = Neck) This Asura was killed by an incarnation of Lord Vishnu, who took the similar form of a horse headed human figure.
Read more about this topic: Exotic Tribes Of Ancient India