Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
Apple iMac 21.5" All-in-One Desktop Computer Core i5-4570R 2.7GHz 8GB RAM 250GB HDD Mac OS Mojave Late-2013 w/ Keyboard & Mouse
Memory upgrade: Apple iMac 2012/2013/2014 (Howto)
Apple iMac 21.5 late 2013 2.7 ghz intel core i5 8gb 1600mhz ddr3 | eBay
Apple iMac 2013 (Late) 21.5-inch (iMac 14,3) SSD ,Ram & OSX Upgrades - ZD Laptop Service Centre
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
Install memory in an iMac - Apple Support
Apple iMac 21.5-Inch (Late 2013) "Core i5" 8GB RAM 1TB HDD Intel Iris Pro | eBay