If you want to repurpose an old SSD as a speedy flash drive, this Sabrent M.2 NVMe to USB-C enclosure offers you the chance for a bargain price from Amazon.
The enclosure that he’s using is meant for a 5.25″ optical drive. It comes with a USB to SATA converter which is how he connects the hard drive to the Raspberry Pi serving the files.
You can find SATA enclosures for SSDs and HDDs as well, giving you plenty of options for what you can stick your drive into. Once it’s made portable, it becomes useful for system and file backups.