Made a spreadsheet of enemy types & their enhanced drops, as well the dungeons by enemy types.
This is should help you pick which dungeons to run for the gear you want since some aspects are more common on certain armor types.
Maybe someone else will find it useful.
There have been a few posts with individual testing results that show there is a clear preference between certain item types and mob types, but we don’t have a complete/comprehensive list yet. It’s pretty easy to see for yourself if you run the same dungeon several times in a row and fill your inventory a few times.
The information most widely circulated is the Maxroll list, which is based on pre-release information and has been proven to be incorrect on a few details already. I don’t have a link handy but there were some detailed posts in the official D4/Blizzard forums (PC General Discussion).