Drawing game with multiple tools.

http://bomomo.com/

Free in the App store

https://apps.apple.com/us/app/thisissand/id569414555

https://paveldogreat.github.io/WebGL-Fluid-Simulation/

Make different shapes and press play to hear your song.

https://musiclab.chromeexperiments.com/Kandinsky/

https://musiclab.chromeexperiments.com/Rhythm/

Go through an entire story with a stickman, drawing parts to progress the story. Only the first two episodes are free.

https://drawastickman.com/