There is a nice little MIDI Soundgenerator (about 90$ at Thomann or Amazon).
http://www.midiplus.com/html/MINIENGINE.html
One can choose the sound out of 128 with the data wheel mechanically or by MIDI signal
“Normally” it is controlled by keyboard controller. Inside works the amazing SAM2695 https://www.dream.fr/pdf/Serie2000/SAM_Datasheets/SAM2695.pdf low-power Single-chip Synthesizer with Effects, 64-voice polyphony (without effects) or 38-voice polyphony + effects. I do not have 64/32 fingers and no hand free to turn the data wheel to choose sounds.
Has anybody tried to use this with Sonic PI via MIDI to get a start?