In that awkward transition phase between electromechanical accounting systems used in the 1940s and the introduction of fully digital computers we find systems such as the IBM 604 Electronic ...
All PWM/EN pins are output-capable GPIOs and avoid the strapping pins 0, 2, 12, 15 (except GPIO 2 used as LED only, which is fine — it's only an issue if held LOW at boot, and our default state is OFF ...