So I've noticed a few times that the werewolf in the second boss fight in Blessed Crucible will be hovering above us. I don't think he actually does damage but he just claws at the air and you can put him out of his misery by stampeding him to death or blasting him with arrows and spells.
In Blackheart Haven, the harpies that don't make it all the way down to fight you can still be killed, their bodies will be laying flat in the air and will be lootable but obviously you can't loot their bodies because they're 20 feet above you
Also while we're at it, in Blessed Crucible in the open arena before you fight Troll King, if you kill the mobs really fast (all the dark elves, wood elves, high elves, nords, etc that are fighting each other), then the nord ring leader lady (the one that captured the fire shalks that burned down an entire village in Vvanderfell) will speak all her dialogue at the same time. It's only happened once to me before when I did a group delve daily, but our entire group thought it was super funny