Crucial 16GB Single DDR4 2400 MT/s (PC4-19200) DR x8 SODIMM 260-Pin Memory - CT16G4SFD824A
Crucial 16GB Kit (8GBx2) DDR4 2400 MT/s (PC4-19200) DR x8 SODIMM 260-Pin Memory - CT2K8G4SFD824A 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
Corsair Vengeance LPX 16GB (2x8GB) DDR4 DRAM 3000MHz C15 Desktop Memory Kit - Black (CMK16GX4M2B3000C15)