The board does not have the standard D-type connectors for the keyboard, mouse, COM, LPT and VGA ports. There simply isn't room on the 100mm edge.

A 50-way header has the COM and LPT ports, which can go to IDC D-type sockets. I'd rather it had been one 26-way header and two 10-way headers, as these are the usual headers used and it is easy to find ready-wired cables.

I will need to make up a cable for the COM and LPT ports, but that should not be hard. I already have a 50-way to LPT cable that I made for a previous project, but I will have to order and fit two COM sockets.

The VGA header has 10 pins, there are no I2C signals nor any standard pinout. The nearest one I have seen is a 16-pin header with IDC cable wire 1...15  going to VGA pin 1...15, with wire 16 unused.

There is a 14-pin header carrying signals for the mouse, keyboard, speaker and battery rail. I bought a Y-cable splitter which has the mouse and keyboard signals on separate pairs of pins:

https://old.pinouts.ru/InputCables/Ps2KeyboardYThinkpad.shtml

https://en.wikipedia.org/wiki/PS/2_port#Port_availability

Normally pins 1 and 5 are used for both keyboard and mouse, but pins 2 and 6 carry the mouse signals in a combined cable.

Needed per board:

50-way IDC socket + 50-way ribbon cable.
26-way IDC socket  + 25-way IDC DB25 connector for LPT port.
14-way IDC socket for keyboard, mouse, speaker, etc.
10-way IDC socket + 15-way Mini DB15 connector, for VGA .
10-way IDC socket + 9-way IDC DB9 connector, two of each, for COM ports.