ALL-IN-ONE Package: Guitar Chords, Chord Progressions, Guitar Scales, Triads, Arpeggios, Notes On The Fretboard, Reverse Chord Finder Tool, Chord Quiz, Alternate Guitar Tunings and Chord Scale Relationships. Guitar Chord Encyclopedia: This handy app includes over 3000 of the most commonly used guitar chords, as well as information on chord theory and easy-reference diagrams.