Though the Far Seers were thought to be an orcish tradition, it appears that all highly accomplished shamans are Far Seers; Nobundo is referred to as a "Farseer", in spite of the orcish tradition.
Orc Far Seers
The Far Seers are an elite group of ancient orcs who represent the pinnacle of shamanistic power. These powerful shamans, who preside over matters mystical for the Horde, are counted amongst Thrall's closest advisors and are constantly in tune with the workings and maneuverings of the Horde. Far seers are not only tied to the elements of the earth and sky, but are also adept at foretelling the future. Their wisdom is outshined only by their courage and ferocity in combat. When the enemies of the horde advance, the far seers mount their loyal dire wolves and wade into battle wielding all the elemental powers of their shamanistic birthright.
Far seers are some of the most respected shaman in the Horde. Most of them ride great white wolves to battle - some say this practice is in homage of the Frostwolf clan, of which Thrall was the warchief before he united the Horde. The orc far seer is the most respected of shaman. He is not a dedicated battlefield mage, however the guidance provided by his visionary powers can prove to be more valuable than a dozen skilled warriors. In combat, a far seer prefers to sit back and summon spirits to do his bidding, but if he's pressed into melee, he can be a formidable adversary.Template:Cite
In addition to being the Warchief, Thrall is also an accomplished and practicing Far Seer. He was trained by the ancient Far Seer, Drek'thar.
Far Seers in Warcraft III
Far Seers can be granted visions of distant places and summon both the elements and Spirit Wolves to protect them. Far Seers also have a 
[Chain Lightning] spell. Perhaps their most powerful spell is the ability to summon the element of earth to induce a massive 
[Earthquake].
Notable Far Seers
Thrall, Drek'thar, Nobundo, Umbrua, Gar'dal Grimsight, Negal Fireye, Kazil Darkeye, Magis Coldeye, Bale Bleakstare, Gorr Grimwolf, Kag'ar Winterfang, Nazgrel, Morg Wolfsong, Kazragore, and Fenris'ar Gul.