I have something similar for my electronics projects, but a bit more "physical" I guess. I had trouble with having multiple ongoing projects, and parts/tools for them intermingling and taking up desk space. I ordered some cheap plastic trays from AliExpress (I think they were meant to be parts of a bathroom organizer or something), which have enough depth to contain boards, components, specialized tools, etc., and stack well. When I need to shelve a project (usually because I'm waiting for parts or I need the desk space), I put everything related to it in an empty tray and put that tray on top of the stack. When it becomes unblocked or I have some spare time to work on something, I pull out the tray and already have most of what I need
Yup seeing the first picture at first I thought it would be some hack involving literal pizza boxes to do some ghetto build simulating good old... "pizza boxes" (the ones I fondly remember are the SGI Indy and then I guess the Commodore C128D qualifies too).
Nor about my circa 2003 gaming PC cobbled together from leftover parts from past builds, using copper wire to provide a common ground that pizza box cardboard cannot.
Unexpected, but fun!