OWC 1866D3R9M64 64.0GB 4 x 16.0GB PC3-14900 DDR3 Mac Pro Late 2013 RAM Memory Matched Set - 4 x 16GB
How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube
OWC 8GB PC3-12800 DDR3L 1600MHz SO-DIMM 204 Pin CL11 Memory Module Upgrade Compatible with iMac, Mac Mini, and MacBook Pro (OWC1600DDR3S8GB) at Amazon.com
32.0GB OWC Memory Upgrade Kit For 2010-2011 Apple iMac
OWC 64GB DDR3 1600 MHz SO-DIMM Memory Upgrade Kit
Amazon.com: OWC 32GB (2 x 16GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S32P) : Everything Else
16GB Memory Upgrade for MacBook Pro, iMac, and Mac mini