Could probably use some more detail. Like how do we go from bland/boring to "evil" seems like sort of a leap. What do you find bland/boring? How exactly do you want things to be darker, or more evil? So on and so forth. I mean you don't necessarily need "Muahahaha I sterotypically evil overlord taken over the worldd!" to make things not bland and boring.
Anyway...
Blood and Mud
Windfall
Blackwood Company
Servant of the Dawn
Dremora Companion
*insert dark brotherhood and necromancer quest mods here*
Integration: The Stranded Light (more "gray" than "evil", but truthfully black and white moralities and themes is like the very definition of "bland".)
Vows and Covenants
Training Cattle.
Hmmm, I wonder if any of those "evil mods?" topics are still around.
EDIT: Yep, here's one from http://www.gamesas.com/topic/1072579-the-any-mods-list-of-topics/:
http://www.gamesas.com/topic/1088911-mods-for-an-evil-character/
Necromancer topics:
http://www.gamesas.com/topic/1092158-a-solid-necromancy-mod-for-oblivion/
http://www.gamesas.com/topic/1076900-necromancy/