Fast Experience 50-60: World Quest Item One-Shots Multiple Mobs (Patreon)

The southern Bastion world quest "Vesiphone's Vicious Vesper"

https://www.wowhead.com/quest=59680/vesiphones-vicious-vesper

has an exploitable quest item. 

First use the action button "Purity Chime" and kill enemies in the area to reach 100% on the progress bar. 

DO NOT complete the quest by killing the Coalesced Fury as you are supposed to. Instead use the now "Empowered" Purity Chime. You will find that it one-shots the aberrations in the area and stuns everything else. This makes for some very fast mob grinding. The mobs killed by the chime award full experience.

By gathering up all the aberrations in the area  and using the quest item you can gain fast experience. This is very fast when done efficiently with rested experience.

I have timed this article to be released when the quest is up. When this article was published it is up for 11 more hours in EU and 19 in North America. (Sorry EU I had unavoidable family commitments earlier)

Note that we have quite a number of active leveling exploits in the archive if this quest is not up when you read this.

EDIT 08/10 Partial nerf, chime now does half damage. This is still useful for some specs though because if you have good area of effect damage (eg arcane damage) you can finish off the aberrations when they are still stunned and there isn't any real practical difference. This is no longer worth it for single target specs though.

For those who liked this one I found something similar I'll upload shortly when the world quest is active.