This is an enclosure for two 3.5" SATA hard drives that need to be connected through SATA-to-USB adapters. My particular need is to connect to a Raspberry Pi, so I included accommodations for a Pi case.

My media server died, and I wanted to replace it with Plex running on a Raspberry Pi, but the dead server is a desktop and uses 3.5" hard drives for media storage (even if it didn't, those are cheap, so that's the route I probably would have chosen anyway).

I couldn't find anything to suit my needs, so I fired up OpenSCAD and made my own.

This enclosure worked so well for our Plex media server, I decided to print another so I could add cheap hard drives to our RetroPie system and expand its capacity. Now I have a black one hiding in a cabinet and a purple one for everyone to see.

This was designed to hold two drives together (a main drive and a backup, in my case), capture/hold the SATA-to-USB adapters for those drives, and screw a Raspberry Pi case onto the drive enclosure. You will need to print the matching Raspberry Pi case, which is here:
https://www.thingiverse.com/thing:922740

I've printed the linked Raspberry Pi case more than a dozen times (I even made a remix for CNC routers), and it's the best one I've found for my needs. Others can be attached to this HDD enclosure with little or no changes - I just included mount points for the one I prefer, which turned out to be easy since it was designed with VESA mounts.

Assembly info is in an attached PDF file.