Talisman of the Wild

The Talisman of the Wild is a mystic stone summons 1 Furbolg to fight for you. Lasts 180 seconds.

Source
Tyrande and Furion can find this in Brothers in Blood, chapter 5 of the Warcraft III night elf campaign, Eternity's End.

Warcraft RPG
Also known as an Amulet of the Wind, this golden amulet is decorated with a scene portraying the night sky, with the constellation of the Bear clearly marked. At twilight, the shape of a bear-like creature can be clearly seen in place of the constellation.

The amulet can call forth a friendly furbolg as a fighting ally once per day. The furbolg is always the same each time, the actual creature having been entrapped within the amulet and forced to serve.