All I have done here is take the excellent Rack for External Toshiba HDD Drive by @dronestationpro and modified it to fit all the different external 2.5" drives that I use. I've remove a section of the front because I like to label the front and back of the drives with an identifier. Due to the modifications these are not compatible to be stacked with dronstationpro's original.

Notes regarding using 2.5" external HDDs:
Probably like most of you reading this, I have been using 2.5" external HDDs due to their good price per TB. This has worked great in a 2018 Mac Mini but I have had a few problems on other devices.

2012 Mac Minis have an Intel CPU that has a hard limit on external USB HDDs of around 12. This is due to the root USB controller.

I wanted to upgrade from my 2018 Mac Mini to a Proxmox server so I could put a beefy GPU in there for Plex transcoding. This is where I found that high capacity 2.5" external drives use something called SMR (Shingled Magnetic Recording) and that Proxmox's default ZFS will give you regular IO errors due to the latency of this technology. There is probably ways around this, e.g. not using ZFS or directly passing the USB devices through to the client. But I ended up just using my Mac Mini 2018 as an expensive NAS.