G.Skill F3-2400C10D-8GTX 8GB (2 x 4GB) DDR3 PC3-19200 2400MHz TridentX Series CL10 (10-12-12-31) Dual Channel kit at Amazon.com
Amazon.com: OWC 32GB (2 x 16GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S32P) : Everything Else
Amazon.com: Corsair CMY16GX3M2A2400C11R Vengeance Pro 16GB (2x8GB) DDR3 2400MHz PC3 19200 Desktop RAM, Red 1.65V : Cell Phones & Accessories
G.Skill Ripjaws X Series 16 GB (2 x 8 GB) 240-Pin SDRAM (PC3-12800) DDR3 1600 CL10-10-10-30 1.50V Dual Channel Desktop Memory Model F3-12800CL10D-16GBXL at Amazon.com