>>715692939
Pretty much all retro FPS have a modern port or they are new enough where they run on modern systems. 3D on DOS is a very narrow time frame.

Serious Sam first and second encounter
Quake 1 and 2
Quake has a lot of good map maps, for example Arcane Dimensions
Doom has a ton and I mean TON of great map packs. you could just play doom wants for the your entire life and you wouldn't be done.