Hell, if we're going to get into MW mods, we can talk for hours. I'm running 200+ on my PC, and there are more than 4000 available, currently.
They run the gamut: bug fixes, utilities, tweaks, ease-of-operation add-ons, quests, races, items, merchants, dungeons, etc. There's even a mod that lets you breed horses (with four attributes) and hire trainers to develop mounts, and another mod that let's you control all aspects of running a mining company.
I suggest checking out Morrowind Summit (which has a database that's searchable by mod category) and TESmods (which provides a lot of detail) for mods.