Interactive guitar fretboard with scales and chords
Zoom in on relevant part of fretboard
Many scales and chords to choose from (Is based on, and supports, all the chords and scales in the [musthe package] (https://github.com/gciruelos/musthe).
Show intervals as well as notes
Customize tuning to your liking
Command-line options available
Newest functionality: Click on labels to toggle transparency, right click to switch root note.
Newest functionality: Now supports other-than-six strings and settings file
Compiled versions for Linux and Windows. Check out "releases".