Use PCB soldering to adapt a Mega Drive pad to MSX
I fit a DA Retro switchless region free mod to a PAL Mega Drive, with a tri-colour LED and no toggle switches, then see how much 60Hz really changes.
A £15 portable Grundig colour CRT with all its paperwork, tested as a retro gaming monitor with a Spectrum, a C64 and a 60Hz Mega Drive.
The Atari 7800 deserved better controllers. I build a small adapter that lets you use a Sega Mega Drive pad on the 7800, then put it through some games.
Plugging a Mega Drive pad straight into a C64 can kill the CIA chip. I build an open source adapter that makes it safe, and works on the Amiga too.