If an item says “Obtained from any suitable loot source but has an increased chance of dropping from ___” on the wiki, you could potentially find it in a bullymong pile, the odds are just virtually non-existent, but its possible. Raids have these in their pools, and have a nice chance to drop them. Pete is the king of loot, having impressive odds to drop just about anything. Generous pete indeed.
What is a man?! A miserable little pile of secrets!