RockDice
Web – https://zvoog.app/RockDice/main.html
Android – https://play.google.com/store/apps/details?id=rockdice.chord.progression
Android (no Ads) – https://play.google.com/store/apps/details?id=surikov.rockdice.addsfree
Look to source at https://github.com/surikov/webaudiofont
More examples: