[throwaway675309]

https://www.sightreadingfactory.com/

You may want to look to Sight reading factory. They do a pretty good job allowing you to dynamically generate unlimited sheet music according to your pianistic capability.

[ask_b123]

this reminds me of this rhythm generator I’ve been using for similar (albeit perhaps more limited) purposes: https://myweb.fsu.edu/nrogers/Rhythm_Generator/Rhythm_Genera...

[sbrother]

Oh, this is awesome, and I hadn't heard of it. Thank you!