Amazon has the Cooler Master Vertical GPU Holder Kit (Supports PCI-E 4.0, Black; ‎MCA-U000R-KFVK03) on sale for $50 with free shipping. Fits all standard E-ATX, ATX & mATX cases (max 70 mm CPU cooler in height available for Micro-ATX) with at least 4 available PCI slots for mounting.