OWC 64GB (2 x 32GB) PC21300 DDR4 2666MHz SO-DIMMs Memory Ram Module Compatible with Mac Mini 2018, iMac 2019 and up, Dell, HP, Lenovo, ASUS and Compatible PCs (OWC2666DDR4S64P) at Amazon.com
G.Skill Ripjaws 16GB 2 x 8GB DDR4-2666 PC4-21300 CL19 Dual Channel SO-DIMM Memory Kit F4-2666C19D-16GRS - Micro Center
32GB Kit MP7N2G/A (2 x 16GB) 260-Pin DDR4 So-dimm RAM | Memory for Apple Woman Owned Small Business. Ready to Ship!
V-Color 64GB (2 x 32GB) ECC SO-DIMM DDR4 2666MHz (PC4-21300) for microservers, workstations, Networking Platforms and Embedded Systems 2Rx8 CL19 1.2V (TES432G26D819K-VC) at Amazon.com