Well, alot of herbalists know this one already, but alot, a surprising amount, in fact, do not. Here you go:
Talonsworn Forest-Rager - NPCs - World of Warcraft
These guys. Talonsworn forest ragers. These guys are, for some classes, insanely easy to kill (I'm a hunter, but my warlock and mage friends can do it easily), and drop insane amounts of mats. There are usually about 6 of them at a time, and you can usually run into all of them with a simple circle around skettis. If you ever run out of them, they have a nice respawn time, and you can always farm dusts in the meantime.
Hope this helped!