Apple iMac (27-inch, September 2013) review: New processors and faster Wi-Fi for Apple's slim desktop - CNET
Amazon.com: Sintech M.2 NGFF 28Pin SSD Adapter, for Read SSD from MacBook 2013-2015 Year in M-Key Slot (Only Fit in Desktop,Height 10mms,NOT fit in Laptop or External USB Case) : Electronics
Amazon.com: Apple Genuine SSD 256 GB NVMe Flash Storage Upgrade Kit for MacBook Pro Retina, Mac Pro, iMac Models. MZ-KKW2560 655-1993A : Electronics
Amazon.com: MCE Technologies 1TB SSD for Mac Pro (Late 2013): PCIe-Based 4 Lane (x4) NVMe SSD Flash Storage Upgrade - Requires macOS 10.13.x (High Sierra) or Later : Electronics