The modded Doom community is pretty incredible but that should be old news :P. I'm fairly certain that at some point theres gonna be some Doom 2016 demake maps, resembling those from the new Doom games but for the old engine. Good times to be a Doom fan for sure.
If Doom is your thing, be sure to check out Prodeus which is going to see a GOG release as well.
Linko64: one likes two, one six nine
tinyE: 6 + 4 + 3 = 2
Those are some quick maths right there.
Linko64: For those into this kinda thing, you may wanan check this little beast...
Holy shit this actually looks fantastic. Hopefully this is going to be released (on GOG) at some point. Games like those fit on the GOG store as well as on itch.io.
EDIT: Edited because GOGforums PHP frontend freaked the fuck out.