go to the location shown in the following pictures:
https://i.imgur.com/5wGMlVW.jpg
https://i.imgur.com/RcH1Zkd.jpg
the video: https://www.youtube.com/watch?v=u3Qbrha8laY
POSSIBLY DRUID ONLY (somehow I can only get it to work with flight form today)
get some distance from the mine shaft (I usually fly to the ocean west of the mine) and then fly into the shaft, you'll get dismounted but remain as fast as if you were still mounted, I'm not entirely sure if it's only 100% or more. Damage doesn't break it, nor does swimming or casting spells. Mounting and speed buffs like Sprint negate it, not sure about slows but they probably cancel it too, loading screens cancel it too. You can run all the way to Elwynn and duel people while you run really fast. Serverside, had several people ask me why I was so fast.