ChordIQ - Learn notes, chords, sight reading, perfect pitch and more.
soundrop - Soundrop is an app that allows you to create your own personalized sound track to keep you focused or relax.
Scale Heaven - Browse and play any scale/chord, chord progression.
muted.io - A magical collection of interactive music theory tools & visual reference pages for musicians and music producers
7Pad Scales and chords - Music instrument and assistant for playing scales and chords.
ChordPic - Create beautiful guitar chord diagrams