Farming Eternals
The best place to farm Eternals is Wintergrasp, Specialy if your faction controls the zone. If your faction controls the zone an other mob named Revenant will be visible.
The Revenant has an 100% Chance to drop some Crystallized Eternals. It spawns for Fires, Waters, Lifes, Shadows, Earths and Airs in Wintergrasp.
Earths about these lakes, Air at the southern lakes, Eternal Waters are located in / at the lakes, fire on the east plateau and Life and Shadow in the ridge at west
The best place for farming / gathering eternals is in Wintergrasp. But some places are better for each Eternals.