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
ADATA 8GB Premier DDR4 2400MHz 260-pin SO-DIMM Laptop Memory Single (AD4S240038G17-S) at Amazon.com
SK Hynix 8GB DDR4 1Rx8 PC4-2400T HMA81GS6AFR8N-UH SO-DIMM Laptop RAM Memory at Amazon.com
ADATA Premier 8GB Single DDR4 2666Mhz CL19 PC4-21000 260-Pin SODIMM Memory RAM Single (AD4S26668G19-SGN) at Amazon.com
G.Skill F4-3200C16D-16GTZR Trident Z RGB Series 16 GB (8 GB x 2) DDR4 3200 MHz PC4-25600 CL16 Dual Channel Memory Kit - Black with Full Length RGB LED Light bar at Amazon.com
Silicon Power DDR4 RAM 16GB (8GBx2) Turbine 3200MHz (PC4 25600) 288-pin CL16 1.35V UDIMM Desktop Memory Module (SP016GXLZU320BDA) at Amazon.com
PNY Performance 8GB DDR4 DRAM 2666MHz (PC4-21300) CL19 (Compatible with 2400MHz or 2133MHz) 1.2V Notebook/Laptop (SODIMM) Computer Memory RAM – MN8GSD42666 at Amazon.com