8GB DDR4 2666 2667 MHz SODIMM Mac Memory RAM for APPLE iMac 2019 5K Retina A2115 | eBay
Crucial 32GB 2 x 16GB DDR4 SDRAM Memory Kit For iMac 32 GB 2 x 16GB DDR4 2666PC4 21300 DDR4 SDRAM 2666 MHz CL19 1.20 V Non ECC Unbuffered 260 pin SoDIMM - Office Depot
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
Crucial 16GB DDR4-2666 SODIMM Memory for Mac | CT16G4S266M | Crucial.com