After a bit of exploring I found two nice places to farm in Act 3.
You have to go out to the battlefields, then run out a little bit into Arreat, refer to screenshots for maps.
Be aware, there will be some mobs in between you and these places, but I'm sure certain classes can just fly by them. Also with the outside chests, 4-6 Winged Moloks spawn so be prepared to loot and run.