SAMSUNG M471A1K43CB1-CTD 2666MHz Memory Modules (8GB, 1 x 8GB, DDR4, 2666 MHz, 260-Pin SO-DIMM, Black, Green) at Amazon.com
HP S1 Single RAM 16GB DDR4 2666MHz CL19 Laptop Memory - 7EH99AA#ABC at Amazon.com
G.Skill Trident Z RGB Series 16GB (2 x 8GB) 288-Pin SDRAM (PC4-25600) DDR4 3200 CL16-18-18-38 1.35V Dual Channel Desktop Memory Model F4-3200C16D-16GTZR at Amazon.com
Amazon.com: OWC 8GB (2 x 4GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S08P) : Everything Else