When the Pi Pico was first launched, there was talk about using its I2C capabilities to run DVI outputs, which is to say to drive a digital display. here already exists a Pi Pico DVI library called PicoDVI (https://github.com/ Wren6991/PicoDVI) that enables a Pico to control a digital display over HDMI.
Utilising this, Clem Mayer, after initially running into timing issues when attempting to directly connect the HDMI to the Pico, found more success once he used a Pico DVI Sock (https://github.com/Wren6991/Pico-DVI-Sock), which is a small PCB that sits under the Pico with an HDMI mounted on it.
Mayer successfully initiated the new pseudo Pico GPU with a Hello World display. To turn his creation into a true GPU, he devised a PCIe PC expansion card to mount the Pico to and host the HDMI connector, which while pushing the definition a bit, is a Pico-powered PC graphics card. See www.youtube.com/watch?v=8-RuYM-9s3A
Behold the world’s first Pi Pico GPU expansion card. No, it can’t play Crysis.
CREDIT: Element14 Presents, YouTube