Don’t forget Forth, specifically zeptoforth, on the PicoCalc, as is detailed at FORTH on the PicoCalc - #5 by tabemann – note that the relevant branch of the GitHub repo is at GitHub - tabemann/zeptoforth at picocalc-devel with directions at zeptoforth/USING_THE_PICOCALC.md at picocalc-devel · tabemann/zeptoforth · GitHub .
While it requires a bit of setup at the moment, and is strictly speaking beta at the present, it is quite functional as it stands. I would highly recommend it to anyone who wants to get more out of their PicoCalc.