I have come to the conclusion that the most diffcult enemies you will face in a given instance are the other members of your pug.
I had heard that warlocks could solo Krastinov and Gandling, but I hadn't seen any movies showing that, so I decided I'd just make one. This is me soloing Scholomance on my warlock. The clips are from several different runs, but all during the most recent patch. (1.12.1). All bosses except Jandice and Kirtonos are included..