A test room I was given to make for a job interview. The requirements were the textures had to be 512x512, and the whole room couldn't be more than 6000 tris, no normal maps and all just diffuse materials. I built it in Blender then imported it into Unity for review. The build was about 8 hrs work spread over 3 days. The majority of the time was spent on designing the room out on paper and figuring out what I could and couldn't do with the room.
For example, I removed the strips that players couldn't see due to not being able to squat or jump, which gave me more triangles to work with. But in future, it would be all self-contained.
I figure if I can get VRChat importing to work this would be a nice meetup place for people.
The inspiration I went with was a mix of the Deus Ex Human revolutions White room with the final scene from 2001: A Space Odyssey. I threw in a red door to add to the suspense.
The White Room