To note a few of these packages/projects:
- elm-audio: Play sound effects and music in a declarative way by @MartinS
- elm-music-theory: Work with musical concepts by @duncanmalashock
- emusic: DSL to write music patterns that looks like those available at sequencers, drum machines and daws. Based on HMusic. by @lgcantarelli
- elm-piano: Simple piano wigdet for Elm programming language by @cript0nauta
- elm-chords: Parse chords sheets for guitar and ukulele in Elm by @Arkham
These are packages available from the official repository, there might be other projects which I’m not familiar with at the time.