That's the best part of Notrium, it really is a timeless classic.
Anyway... Latest/Only Mods of note:
Werivar Expansion was made a few years back after Uberwaffe abandoned his project to be taken on by a strapping young fellow of excellent breeding. The W.E's got some advanced features and an extra player race over the standard Werivar mod, along with some bugfixes. It can be found, as with so many mods, on Harwe's Box Account. http://www.box.com/shared/uqmfikmoe6 unless otherwise noted, this is the same place to find all the following as well.
SOS is a short one, I believe it's hosted on the site, you're a cyborg trying to survive after your spaceship crashes. It has some neat effects on it, but it never got too far from what I recall.
Aleryon Betrayal took the Notrium engine and made it into a solid action game, kinda like a cross between Doom and Gauntlet for my money, or possibly Smash TV. It's got a lot of great features and last I recall is pretty long.
Wazzal II is a ship to ship combat game following on from the adventures of the Captain after he escaped from Notrium. It got pretty far in development if I recall, and had some sweet ship to ship combat.
Then there are two mods I know of in progress right now, you can probably find recent versions and more about these ones on the forums in their respective threads.
Planet Pandora - Its premise is pretty similar to S.O.S, your ship has crashed on a planet and you need to repair it. It's only in alpha right now, and INFERNUS hasn't updated or given any news for a bit, but hopefully we'll see something more from this soon.
And lastly there's Notrium F.M, this one's a remake of Default Notrium from scratch, with new scripting, items, weapons and features. So far there're only two characters - the Android and the Captain, and a few areas.