Timetec Hynix IC 8GB KIT(2x4GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 for Early/Mid/Late 2011, Mid/Late 2012, Early/Late 2013, Late 2014, Late 2015 MacBook Pro, iMac, Mac Mini (8GB KIT(2x4GB)) - Walmart.com
A list of successful iMac 27" (2012-2019) SSD upgrades | MacRumors Forums
Amazon.com: OWC SSD Upgrade Bundle for 2012-2019 21.5" iMacs, Mercury Electra 1.0TB 6G SSD, Express 2.5" USB 3.0 HDD Enclosure, Installation Tools and iMac Screen Adhesive Tape Set : Electronics