Sky drops
 

Haven't seen/don't recall and wiki isn't showing (I know its not completely official...)

Drops on Keeper of Souls: whitened treant fist
https://farm8.staticflickr.com/7442/...be44d63d_z.jpg

An essence carrier: blade of abrogation:
https://farm8.staticflickr.com/7442/...be44d63d_z.jpg

A soul harvester: all haste belts (at least belt of pine)
https://farm8.staticflickr.com/7224/...6146a219_z.jpg

have seen all those items drop from those creatures you mention.

Every haste belt from those horses and have had the monk fists drop from Keeper.

also silly SK epic thing has dropped from plenty of isle 4 trash