Noah Zark POST #54 is the finest description of PID controllers I can remember reading.
Someone else still remembers Foxboro and Fisher pneumatic with the pen dragger charts.
Don’t forget Hagan / Westinghouse boiler control that was a real work of art. No chart but the balance beams for gain were interesting
I don’t know if I still have any pictures of one.
I copied it and sent to an old work friend that retired quite awhile after I did