Jazz Buddy App for iOS
'Jazz Buddy is a simple program intended for jazz musicians that links chords to relevant scales. You select a chord and it will display the scales you might play against that chord. The end result is a list of the chord notes, scale notes, and a representation of the scale played on a piano.
+ Chord types: major, minor, dominant 7th, half diminished, diminished.
+ Most common jazz-oriented chords.
+ Common jazz scales including major, dominant, blues, whole tone, diminished and many more.
+ Playable keyboard with the notes of the scale overlayed.'
This app costs $1.99