Amazon.com: Crucial RAM 16GB Kit (2x8GB) DDR4 2666 MHz CL19 Memory for Mac CT2K8G4S266M : Everything Else
Amazon.com: Crucial RAM 32GB DDR4 2666 MHz CL19 Memory for Mac CT32G4S266M : Everything Else
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