During one of the earliest quests in the game, The Fallen Star, you're given the objective to kill the Wretched Queen north of New Tristram. At the same time, you're given the "Bonus" objective of killing three Wretched Mothers.
I'm doing my second playthrough of the game, in Nightmare mode now, and it occurred to me that since I've already been everywhere and seen everything, I might not want to complete all of the quest bonus objectives, but I have no idea what they are, or what the rewards are.
Does anyone know what bonus quest objectives exist, and what the rewards are? Knowing this would help me streamline my second playthrough without missing any important rewards.