I was commissioned to design some open-source boards which are used with the original Microsoft Xbox. The LPCorrectr addresses an issue with certain versions of the Xbox and the OXControllr allows a USB drive to be used as a memory card.
Both of these boards are very simple from an electronics standpoint, most of the work was in measuring everything and trying to account for the manufacturing tolerances of the boards themselves and the Xbox’s they would be used with. As such, I started by creating sketches in FreeCAD of the critical connection points and whatever cutouts would be needed to make the boards fit before designing the boards in Altium.
(I have more images here)