During the 4-5 years I played Descent on a regular basis, I developed a number of multiplayer levels. Most of the earlier material was not particularly inspirational, but the quality started to improve from the end of 1998.

I don't have copies of many levels, but the better ones have survived through online level archives, particulary PlanetDescent and descent2.de.

The most notable releases were, in order of release: Disintegration (levels 2, 4 and 6), difFusion, Nuclear Hoard (2 and 3), Backwash, Discus, Magnacore, Epona 2, Noble Gases (all) and Desert Colossus.

Steinlager has survived as well, though was a gimmick rip-off of Keg Party and thus not too exemplary.

Dark Matter has likewise turned up on descent2.de. It was one of my earliest levels, dating back to 1998. However, a lot of weapons have been added and a few brownish cubes with lava at the ends of them were added as well. The timestamp was 2003, so it's well after I stopped building D2 levels, and five years after that one. Deathwinger is the only one I know of who could have kept that level, so I suspect he made the alterations.