Cooler Master has created a graphics card vertical mount kit called the Vertical Graphics Card Holder Kit V3 that can be mounted to pretty much any standard PC case. 

Vertical graphics card mounting kit that is compatible with a broad range of popular (including E-ATX) ATX and MicroATX chassis. It is compatible with ordinary PC chassis of both ATX and MicroATX sizes and may be installed if there are four expansion slots (manufacturer). The kit also includes a 165mm riser cable that is PCI Express 4.0 compliant (x16). Made of high-quality SGCC steel to withstand distortion and flexing caused by the graphics card's weight. In order to be compatible with graphics cards that use flow-through cooling, a design that allows for ventilation is used.It has an easy-to-follow installation technique that allows you to mount the graphics card after positioning the holder. The holder can support graphics cards up to three slots thick.

External measurements are 148.1 to 178.1 mm wide, 249 to 305 mm deep, 141.8 mm tall, and 810 g weight. In theory, it corresponds to a PC case with a width that can cover the complete height of the CPU cooler, which is 70mm, and it is said to interfere if parts are mounted to the back panel. This kit will cost roughly 75 EUR.