I had a case for secure transport of HDDs and wanted to use one of the free slots for storage of M.2 ssds. It fits standard m2 nvmes, approx 80x22mms. Pictured is a samsung 970 evo.

The design is very simple but not very easy to print. I printed it upside down (the slots facing the buildplate) using variable layer height for the couple of layers where it bridges the top of the cut-out cylinder. 0.28mm apart from that. I had to add the center piece because in my box there were gaps in the foam on the sides where it could get kinda stuck in otherwise.

I initially made it to have 10 slots as I will never have more, but quickly made another with more slots for anyone looking to maximize storage. It is untested however.