I found a fast way to farm champion packs in Act 2.
There is also a chance of treasure goblin!
How is it done:
#1: Start a game in Act 2 at any quest as long as you have Dahlgur Oasis.
#2: I choose Blood and Sand and then I hire leah (she is weak but all damage helps) I also hire a merc for mf.
#3:Teleport to Dahlgur Oasis
#4: Scout around the waypoint, making going 10 - 15 seconds in every direction around the waypoints, you should be able to find a champion pack.
#5:Find champion pack and get it very low and dont forget to swtich to mf gear if you have it!
#6: Kill the champion pack, loot, teleport to town, leave game. Resume game and do it again.
Its A2 loot so some of it is decent, I got some upgrades for my merc. I do it with a 100k DH and some of the mobs are pretty tough, if you die you spawn on the waypoint so I try to keep the mobs around the waypoints.
I also use the bushes to my advantage and run around them, its very easy to kite the mobs that way.
Enjoy and sorry if repost!