The Raspberry Pi Compute Module 5 single board PC supports one PCIe 3.0 lane, which is usually used to connect M.2 SSDs. But the new Sentinel Core board will allow you to connect a full-fledged video card to it. 

 Photo Crowdsupply

Sentinel Core is a board to which the Raspberry Pi Compute Module 5 is connected. The board has PCIe slot to which you can connect a video card. You won't be able to squeeze a lot out of one PCIe 3.0 line, but for certain scenarios it may be suitable.

But this is not the only purpose the board serves. With dimensions of 170 x 170 mm, the board also has two HDMI, USB-C 2.0, a pair of USB 3.0, RJ45, 40-pin GPIO, and all this costs $130 as part of a launched crowdfunding campaign.