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
Apple iMac with Retina 5K display - All-in-one - Core i5 3.5 GHz - RAM 8 GB - Hybrid Drive 1 TB - Radeon Pro 575 - GigE - WLAN: 802.11a/b/g/n/ac, Bluetooth
Factory Original 64GB (2x32GB) Memory Upgrade for 2020 & 2019 Apple iMac 27" w/Retina 5K Display & 2018 Apple Mac Mini DDR4 2666Mhz PC4-21300 SODIMM 2Rx8 CL19 1.2v RAM Adamanta at Amazon.com
64GB Memory Upgrade for 2019-2020 Apple iMac (27-inch)
Adamanta 16GB (1x16GB) Memory Upgrade for 2020 Apple iMac 27" w/Retina 5K Display, 2019 Apple iMac 27" w/Retina 5K Display, 2018 Apple Mac Mini DDR4 2666Mhz PC4-21300 SODIMM 2Rx8 CL19 1.2v DRAM
Apple iMac 27-inch (2020) Review | Trusted Reviews
Factory Original 64GB (2x32GB) Memory Upgrade for 2020 & 2019 Apple iMac 27" w/Retina 5K Display & 2018 Apple Mac Mini DDR4 2666Mhz PC4-21300 SODIMM 2Rx8 CL19 1.2v RAM Adamanta at Amazon.com
Refurbished 27-inch iMac Pro 3.2GHz 8-core Intel Xeon W with Retina 5K display - Apple
Apple iMac 27 5k retina core i5 3.7 GHz, 40GB RAM, Pro Radeon | eBay
NEMIX RAM Compatible for 128GB (4x32GB) DDR4 2666MHz PC4-21300 SODIMM Memory Upgrade for Apple iMac Mid 2020 (iMac 20,1/20,2) / Mid 2019 (iMac19,1) 27-inch w/Retina 5K, Late 2018 Mac Mini 8,1 at Amazon.com
Adamanta 16GB (1x16GB) Memory Upgrade for 2020 Apple iMac 27" w/Retina 5K Display, 2019 Apple iMac 27" w/Retina 5K Display, 2018 Apple Mac Mini DDR4 2666Mhz PC4-21300 SODIMM 2Rx8 CL19 1.2v DRAM
Best Buy: Apple 27" iMac® Intel Core i5 (3.2GHz) 8GB Memory 1TB Hard Drive Silver ME088LL/A
Apple iMac 27-inch (2020) review: new webcam, new screen option, same iMac - The Verge
Apple iMac 27-inch (2019) review: Apple iMac 2019 is a millennial trapped in the body of a baby boomer - CNET