32GB DDR4-2666MHZ Non-ECC CL19 SODIMM 2RX8 at Amazon.com
Kingston 32GB ECC Reg DDR4 2666MHz (KTH-PL426/32G) at Amazon.com
OWC 32GB (2 x 16GB) PC21300 DDR4 2666MHz SO-DIMMs Memory, Compatible with Mac Mini 2018, iMac 2019 and up, and Compatible PCs, (OWC2666DDR4S32P) at Amazon.com