Here is the #Compupro #S100 card set I put in the system:

There are two more slots free for future expansion.

That empty spot to the left of the floppy drives is just the right size to stash a copy of The CP/M Handbook by Rodnay Zaks.

I think this came from some company that built (or repaired?) hard disk drives. The cards and power harness had been removed, but the case has a nice 7-slot S-100 backplane and a pair of especially nice Mitsubishi M2896 8" floppy disk drives. Back around 2016, I built a new power harness and fitted it with a #Compupro #S100 board set.

The little rack it's in flips right over with the computer rolled out on its rails, so I made a pair of legs with 80/20 extrusion. They're a bit cumbersome to use, but they were easy to make.