In the Last Valley in Stonefields, there is a quest for Fatal Distraction which you fight and then control a troll under 75% health and it helps kill elite Stone Centurions. As long as you don't hand in the quest (obviously) you can repeat this line as much as possible. The Elites respawn pretty fast and I was hitting 950 - 1000xp per kill and since the trolls were tanking they died extremely fast with no damage to me. I know this isn't super extreme fast power leveling but next to no down time and high xp makes its viable farming spot.
They seem to only drop trash but was able to pick up 2 blues from them after an hour.