XFX AMD Radeon RX 580 GTS Black Edition 8GB GDDR5 PCI Express 3.0 Graphics Card Black RX-580P8DBDR - Best Buy
Apple iMac MNEA2LL/A- 5K 27" Intel Core i7-7th Gen 32GB RAM 1TB SSD Radeon
AMD Radeon Pro 580X 8GB RAM MPX Module / GPU for Apple 2019 Mac Pro (7,1 A1991) | eBay
Apple AMD Radeon Pro 580X 8GB GDDR5 MPX Module for 2019 Mac Pro | eBay
Update: now available as standalone purchase] Apple makes the Radeon Pro W5700X MPX Module available in custom Mac Pro builds - 9to5Mac
Computers & Electronics :: Refurbished Desktop Computers :: Apple Desktops :: 2019 Mac Pro Parts :: Apple AMD Radeon Pro 580X 8GB RAM MPX Module for 2019 Mac Pro
Pro W5700X versus other 2019 Mac Pro GPUs
AMD Radeon Pro 580X Specs | TechPowerUp GPU Database
Apple Mac Pro (12-Core w3235, 96GB memory, 580x + W5700x)