Morrowind may be Bethesda's weirdest RPG, but after replaying it a couple of times that alien landscape starts to feel familiar and kind of ordinary. One way to restore its outlandishness is with the total overhaul Morrowind Rebirth, which solo modder Johan Rosen has been plugging away at for over a decade, releasing version 6.0 this month.
Morrowind Rebirth refreshes Morrowind, adding new buildings and NPCs to its settlements, creatures to its wilderness, graphical improvements, extra equipment and music, and generally just more of everything. It's compatible with open-source Morrowind engine replacement OpenMW too.
Version 6.0 includes various landscape changes and improvements, adjusted lighting in the Deadlands to make it "more ominous", multiple expanded interiors, extra weapons and armor including orcish weapons and throwing darts, new trading cards that depict the local saints, and way more. Dozens of textures have been upscaled or updated, and new textures added for objects from Imperial rugs to the Netch Herders' Book of Jokes. Liches have been buffed and now drop greater soul gems, and in a nice change, dead NPCs will no longer despawn if they're carrying valuable items. Those are just some of the changes, which you can see in full on Mod DB.
There's a fancy release trailer for version 6.0, taking in various locations across Vvardenfell as well as some battles with dark elves, clannfear, and skeletons. The trailer was recorded with other mods installed as well, all of which are listed in its description, so if you want your Morrowind to look that foggy and its grass that lush, you'll also need to download Vapourmist and Aesthesia Groundcover for starters.
Morrowind Rebirth 6.0 can be downloaded from either Mod DB or NexusMods. You'll want to grab the Morrowind Code Patch as well, which it's dependent on. Be aware that Morrowind Rebirth conflicts with the RPG's other main overhaul option, Tamriel Rebuilt, so you're better off going with one or the other rather than trying to merge the two into some unholy beast.