y website has been around for a very long time. You're likely to find a bunch of old stuff lying around.
I have gathered some of it here. Don't get your hopes up too high, you probably won't find any lost jewel in the bunch.
Doom and Heretic Mods
My only Doom 2 custom level that is reasonably worth playing.
A custom level for the game Heretic that depicts J.R.R. Tolkien's Moria.
This is a modest rendition of an all-time classic mind-boggling game. The goal is to move atoms
in a small labyrinth so that they create a molecule, within a strict time limit.