Amazon.com: Odyson - 1TB SSD Replacement for Apple MacBook Pro 13" A1502, 15" A1398, Replacement for Apple Mac Pro A1481, 21.5" A1418, 27" A1419 (Late 2013-Late 2014) : Electronics
I got a FREE 2013 iMac 21.5 with internal upgrades including Samsung evo ssd and 16gigs of ram. Then used open legacy patcher to install Mac OS Venture 13.5 beta. : r/osx
Apple iMac SSD Upgrade — Epoch Business IT Solution
OWC SSD Upgrade Kits for 21.5-Inch iMac (2013 - 2019)
Amazon.com: Odyson - 1TB SSD Upgrade Kit Replacement for Apple iMac 21.5" A1418 (Late 2013-Mid 2014) : Electronics
Late 2013 iMac review: Faster than before, but the gains over previous models are modest | Macworld
Apple iMac 21.5” SSD Upgrade (2013-2015) HDD To Solid State Drive (SATA) | Step By Step - YouTube