I didn't know what these were called until I noticed that the wiki has a section dedicated to themes. They have a few examples but I'm interested in your favorites. The definition of them:
A cyberspace map is a level design themed around a "virtual reality" world as depicted in cyberpunk fiction.
Abstract structures in wireframe or solid colors
Streams of scrolling characters
Colored lines
https://doomwiki.org/w/images/0/0b/ZDCM ... onroom.png
A void map is a level design themed around surreal islands of matter floating in an endless void.
Partially erased structures
Upside-down structures
Stark darkness
Shifting colors
Sky floors
https://doomwiki.org/w/images/b/b1/Void ... meplay.png