After six years of hardware ray tracing, the best examples of it are modified old games, like Quake and Minecraft.
There might be a good reason for this. Raster effects were already really good in newer games, and ray tracing could only improve on that high bar. It's filling in details that are barely noticeable, but creap ever so slightly closer to photorealism.
Old games start from a low bar, so ray tracing has dramatic improvement.
Quake was also the first game with texture mapping. At the time, it was fucking amazing, and how, today, modern games can have things like transparency and round corners on polygons on their 3-D models.
Also, when it came out, only, like, two video cards even supported all of the features in the game. It was almost a year before any other video cards came out that did. There was one ATI Radeon card and one Nvidia card. I remember that I had the ATI card that supported the Ray tracing and the texture mapping (Radeon 9800).
What? Because texture mapping showed up much before Quake, wolfenstein 3d had it. And you didn't need any special video card for it, it was rendered by the CPU.