Apple iMac 21.5" Late 2013 - Catalina, 1TB HDD, 8GB RAM, Intel Core i5 2.9GHz | eBay
Adamanta 4GB (1x4GB) Apple Memory Upgrade for Late 2013 iMac 21.5" and 27" DDR3L 1600Mhz PC3-12800 SODIMM 2Rx8 CL11 1.35v RAM at Amazon.com
parts-quick 16GB 2 X 8GB Compatible Memory for iMac 27" inch 3.2GHz Quad Core Intel Core i5 Late 2013 ME088LL/A 1600MHz DDR3 (PC3-12800) SO-DIMMs RAM at Amazon.com
A-Tech 8GB RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
USA 8GB 16GB PC3L-12800 DDR3-1600MHz Memory for iMac 27-Inch "Core i7" Late 2013 | eBay
8GB 2 X4GB Memory for iMac 27" inch 3.2GHz Quad Core Intel Core i5 Late 2013 ME088LL/A 1600MHz DDR3 (PC3-12800) SO-DIMMs RAM (PARTS-QUICK Brand) at Amazon.com
iMac RAM for Model 13.2 to 15.1| DDR3-1600MHz | 8GBx4 | MacMemory.com
Adamanta 16GB (2x8GB) Apple Memory Upgrade DDR3L 1600MHz SODIMM Compatible for iMac (Mid 2011, Late 2012, Early/Late 2013, Late 2014, Mid 2015), MacBook Pro (Early/Late 2011, Mid 2012), Mac Mini RAM at Amazon.com
A-Tech for Apple 16GB Kit (2x 8GB) DDR3 1600MHz PC3-12800 204-pin SODIMM MacBook Pro (Mid 2012 13”/15”), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015, 21.5”/27”, Retina 5K) Memory RAM Upgrade at Amazon.com
Late 2013 iMac updated to Sonoma - runs absolutely fine. : r/OpenCoreLegacyPatcher
Apple 21.5" iMac Desktop Computer (Late 2013) ME086LL/A B&H
Apple iMac 21.5 late 2013 2.7 ghz intel core i5 8gb 1600mhz ddr3 | eBay
A-Tech 8GB RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
CMS 16GB (2X8GB) DDR3 12800 1600MHz Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Core I5 3.4 27-Inch (Late 2013) Me089Ll/A - A7 at Amazon.com
Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3L 1600MHz for Mac Book Pro(E... | eBay
Apple Imac 21.5 - inch, late 2013 2.7 GHz Intel Core i5 8GB 1600 MHz DDR3 | eBay
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
Apple iMac 21.5 late 2013 2.7 ghz intel core i5 8gb 1600mhz ddr3 | eBay