While some mod sites have closed down, others still exist, and some new ones have been added to the lot.
Morrowind Summit is now
PlanetElderScrolls. Awful name, but it has an excellent collection of mods which are checked for viruses, support screenshots, and include both player ratings, and editorial comments about missing readmes, GMSTs, etc.
TESSource is still going strong. The "membership required to download" feature has been disabled for now. Again, support for screens, but no virus checks. Anybody can put anything up--and will. Caveat emptor.
Elric's site has quietly become one of the three big central download spots for Morrowind mods over the last year. No screens and tiny print, but there's space for a modder's home page, votes, and detail. There are some files here you can't find elsewhere--like Kahleigh's excellent splash screens.
Among link sites,
Morrowind Mythic Mods remains one of the best, possibly the best. It has an excellent structure that includes subsections for realism mods, themed mods, and how to use mods. Another excellent site is
Telesphoros' list, a selection of links to some of the finest mods in a variety of areas, with good descriptions. Both of these lists are updated regularly.