Theory

Basics:
>https://openmusictheory.com/
>https://viva.pressbooks.pub/openmusictheory/
>https://ycmusictheory.commons.gc.cuny.edu/about/
>https://open.umn.edu/opentextbooks/textbooks/257
>https://open.umn.edu/opentextbooks/textbooks/fundamentals-function-and-form-theory-and-analysis-of-tonal-western-art-music
>https://www.musictheory.net/exercises

Electronic:
>https://en.wikipedia.org/wiki/List_of_electronic_music_genres
>https://blog.waproduction.com/music-theory-101-for-edm-producers-part-1
>https://music.storypro.io/
>Music Theory, Harmony & Composition for Computer Musicians – Michael Hewitt
>The Theory and Technique of Electronic - Miller Puckette