OWC 16GB (2 x 8GB) PC21300 DDR4 2666MHz SO-DIMMs Memory Compatible with Mac Mini 2018, iMac 2019 and up, and Compatible PCs (OWC2666DDR4S16P) at Amazon.com
Silicon Power DDR4 16GB (2x8GB) RAM 2666MHz (PC4 21300) 288-pin CL19 1.2V Non ECC Unbuffered UDIMM Desktop Memory with Heatsink SU016GBLFU266BD2J6 at Amazon.com