Crucial 32GB Kit (16GBx2) DDR4 2666 MT/s (PC4-21300) DR x8 SODIMM 260-Pin Memory - CT2K16G4SFD8266 at Amazon.com
OWC 32GB PC21300 DDR4 2666MHz SO-DIMM Memory Compatible with Mac Mini 2018, iMac 2019 and up, Dell, HP, Lenovo, ASUS and Compatible PCs (OWC2666DDR4S32G) at Amazon.com
Amazon.com: Crucial RAM 32GB DDR4 2666 MHz CL19 Memory for Mac CT32G4S266M : Everything Else
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