I developed some add-ins for the Casio Prizm series of graphic calculators (fx-CG10 and fx-CG20 some add-ins are compatible with the fx-CG50 and Graph 90+E). It’s as easy as looking at the back of your calculator and typing 15 characters. Own a Casio Prizm? Please take five minutes (probably less) to fill my survey on product IDs. Their source code is available on GitHub for anyone who wants to fork them and continue development subject to the terms of their respective licenses. I have stopped developing for the fx-CG series years ago, I no longer follow the custom add-in development scene, my add-ins will not receive further updates. They have not been tested on these versions and I can’t guarantee nasty things are not happening behind the scenes which could damage your calculator.
All of my Prizm add-ins are unsupported on current OS versions.