Amazon.com: OWC 4GB PC19200 DDR4 2400MHz SO-DIMM Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S4GB) : Everything Else
G.Skill Trident Z RGB Series 32GB (2 x 16GB) 288-Pin SDRAM (PC4-25600) DDR4 3200 CL16-18-18-38 1.35V Dual Channel Desktop Memory Model F4-3200C16D-32GTZR at Amazon.com