Felwood Furbolgs

Felwood Furbolgs were a tribe of furbolgs living in Ashenvale during the Third War. When the Orcish Horde and the Human Expedition moved into the forest, their elder shaman decided to leave the place and move deeper into the forests to avoid a corruption. Tyrande Whisperwind assisted him by gathering the scattered tribesmen. When the furbolgs were collected, they evacuated their village and had their champion accompany the High Priestess.

They moved to the Winterspring Valley where they succumbed to the corruption, being near a defiled water pool. Tyrande and Malfurion encountered them again and killed them. Malfurion remarked that he had never seen them so aggressive.

Speculation
The furbolgs that Tyrande and Malfurion found later in the Barrow Deeps beneath Mount Hyjal may have been members the Felwood Furbolgs as she cured a sick elder shaman there. The furbolg chieftain explained that some of their tribesmen had left them. Tyrande responded that she would help them in order to avoid turning feral like their tribesmen, probably referring to the events in the Winterpsing Valley. Moreover, after being rescued, the shaman says that he must thank Tyrande again, implying that the shaman in Ashenvale and the Barrow Deeps one are the same.