>>12130859
There's also Dissolution and Project Slipgate, but their devs felt like remaking them with HD textures and other fancy things which kinda ruins their feel for me. Compendium has both of these in their original releases, at least.
Zaero also kinda felt very Quakey to me, and there's Anomaly Deimos which is its own beast but still feels strangely Quakey.

I'm still getting to grips with the Ad Mortem assets, but I think I have a good idea for the rest of the map and will attempt to make it use mostly white textures and tie it to albedo, one of the steps of the magnum opus in alchemy.
I'm kind of a nerd.