Amazon.com: A-Tech 128GB Kit (4x32GB) RAM for Apple iMac 2019 & 2020 27 inch Retina 5K | DDR4 2666 MHz SODIMM PC4-21300 / PC4-21333 260-Pin SO-DIMM Max Memory Upgrade : Electronics
Timetec Hynix IC 32GB KIT(2x16GB) Compatible for Apple 2019 iMac 27-inch w/Retina 5K Display, Late 2018 Mac Mini DDR4 2666MHz PC4-21300 2Rx8 CL19 1.2V SODIMM Memory RAM Upgrade (32GB KIT(2x16GB)) - Newegg.com
How to upgrade the RAM on the 27-Inch iMac (2020) | AppleInsider
How to upgrade the 27-inch 5K iMac (2019) with a massive 128GB of RAM [Video] - 9to5Mac
Astra Gear 64GB(32GBx2) DDR4 2666MHz SO-DIMM Upgrade for 2020 & 2019 Apple iMac 27" w/Retina 5K Display iMac SO-DIMM Memory Module Ram Upgrade CL19 1.2V (AHA19ASDRAG8T-BG26SD) at Amazon.com
How to upgrade the 27-inch 5K iMac (2019) with a massive 128GB of RAM [Video] - 9to5Mac
Adamanta 64GB (2x32GB) Memory Upgrade for 2020 Apple iMac 27" w/Retina 5K Display, 2019 Apple
How to Upgrade iMac RAM: 2012-2022: EveryMac.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
How to Install Ram on the 2019 27 inch iMac and which Ram to Buy? - YouTube