ULX3S extension boards
Camera extension enables connecting OV7670 to ULX3S FPGA board.
USB extension board enables connecting two USB devices (like keyboard and mouse) to ULX3S FPGA board.
GPDI extension board offers GPDI input or additinal GPDI output for ULX3S
And many more!
https://github.com/goran-mahovlic/ulx3s-extensions
https://github.com/goran-mahovlic/ulx3s-extension-quickstart