Amazon.com: Satechi Aluminum Type-C Clamp Hub Pro with USB-C Data Port, USB-A 3.0 Data, Micro/SD Card Reader - Compatible with 2020/2019/2017 iMac & iMac Pro, Does Not Fit 2021 iMac (Silver) :
Amazon.com: Satechi USB-C Clamp Hub – USB-C Data Port, USB-A 3.0 Data, Micro/SD Card Reader – Compatible with Apple Studio Display and 2021 iMac 24-inch. Does Not Fit 2020 iMac and Earlier
iMac 2019 5k 27 inch Logic Board 3.7GHz 6-Core i5 Radeon Pro 580X 8GB | eBay