Favorite unique(bosses) to farm

Whats your favorite bosses to farm? quickest to get to? looking to start making a list for the campaign for people who want to be able to have plenty of roll attempts on their (random shop rolls).


I'll start.


The frost witch in act one located in "ClearFell" is a really good place to farm early game uniques, roll attempts, and much more to get set up for later going into act 1 and on.