http://www.gamesas.com/?showtopic=1010109
http://www.gamesas.com/index.php?showtopic=1072579 AZERnecro, there's currently 5 on the list.
Moriarcis is decent but has some buggy spells, and one of the final rewards is buggy.
The Necromancer adds a bunch of Necromancer towers around, and a few NPCs. Actually getting into the "quests" and such take a bit of an investment though. (You have to basically give 20 ingredients added in areas added by this mod, to some of the random necromancers that wander around)
Crafty bits, and some variant of it I've heard good things about.
EDIT after checking the topics on my list:
Oh there's also some Mannimarco mods... some make the boss fight harder, more atmospheric, and such. Others allow you to join him after the end of the Mage's guild quest line.
JPM's miniature necromancy
sixth element
The fifth topic on the list is pretty good, too many mentioned mods to list