128GB (4 x 32GB) DDR4-2666MHz PC4-21300 SO-DIMM Memory for Apple 27" iMac with Retina 5K Display Mid 2020 (iMac 20,1 iMac 20,2) by NEMIX RAM - Newegg.com
Mass Production of DDR4 will allow producing 128Gb RAM sticks - ESX Virtualization
HyperX Fury 64GB 3200MHz DDR4 Ram CL16 DIMM Black Single Stick Desktop Memory with low-profile heat spreader (HX432C16FB3K2/64) at Amazon.com
128GB (1x128GB) DDR4-2666MHz PC4-21300 ECC LRDIMM 8Rx4 1.2V Load Reduced Server Memory by NEMIX RAM at Amazon.com
Beware of the single rank x16 RAM kits sneaked in some laptop models! The 1Rx16 modules have significantly lower bandwidth compared to the 1Rx8 variants - NotebookCheck.net News