Around the large lake in Skettis there are 3-5 elite wood elementals called Talonsworn Forest-Ragers. They are lvl 71-72 elites and they have a pretty decent respawn rate. I put for warlocks as they are the easiest to solo these with because you can just fear, shadowbolt, repeat. You can also banish them if you get into trouble. Now they drop crap for loot, but after you loot them you can use herb gathering on their corpse. You will get 4-6 mote of life and 4-8 of the following herbs in different combinations: Felweed, Dreaming Glory, Mana Thistle, Terocone, BLACK LOTUS, and FEL LOTUS. In addition you get 30 skyguard rep from killing these. There are also plenty of Mana Thistle and Dreaming Glory nodes to grab in between kills.
This can be done with other classes solo, or with another person helping, but solo as a warlock is the most effcient way I have tried, and you don't have to share loot. I'm sure many people may already know this, but the lack of people I see attempting these tells me that many don't. Happy hunting.