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
Amazon.com: Crucial 8GB Single DDR4 2400 MT/S (PC4-19200) SR x8 SODIMM 260-Pin Memory - CT8G4SFS824A : Everything Else
ADATA 8GB Premier DDR4 2400MHz 260-pin SO-DIMM Laptop Memory Single (AD4S240038G17-S) at Amazon.com
Corsair Vengeance LPX 16GB (2 X 8GB) DDR4 3600 MHz (PC4-28800) C18 1.35V Desktop Memory - Black (CMK16GX4M2D3600C18) at Amazon.com