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
Synology RAM DDR4 ECC SO-DIMM 8GB (D4ES01-8G) at Amazon.com
SK Hynix 8GB DDR4 1Rx8 PC4-2400T HMA81GS6AFR8N-UH SO-DIMM Laptop RAM Memory 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