Recently, a modder with the nickname Pathtraced Paradise released an RTX remaster of the classic shooter Clive Barker's Undying. He used NVIDIA tools for the job.
The enthusiast replaced over a thousand original textures with high-resolution 2048 x 2048 PBR (physically based rendering) materials.
Clive Barker's Undying RTX Remix Mod is distributed via ModDB, this is an early "alpha" version — so far the modder has worked on the "first hours of gameplay" (in some places, light sources were set automatically; mirrors have not yet been fixed, effects may be buggy). Gameplay can be viewed at the following link.