Natural minor scale is much used in pop, dance, classical and jazz tunes. Pay attention to II degree ( half diminished ) and to VII degree ( diminished seventh ) Natural minor key chord chart Pay attention to IV degree ( seventh chord with augmented 4th) and to II degree (min 7th ) Melodic minor scale is less used than natural and harmonic scales but it is important.
Dominant seventh chord is on V and it has also minor ninth and minor sixth! This scale has minor major seventh chord on the first degree there are major chords on III and VI half diminished chord is on the second degree, diminished 7 on VII and minor seventh is on fourth one. Harmonic minor key is the classical minor scale I think it is the true minor scale because the natural minor ones is similar to the major scale while melodic minor scale is less used.
However, in music you can find every combination of all these chords. Classical pop progressions are I – VI – IV – V or I – III – II – V. I, II or IV, and V are the most used chords. Half diminished chord is on the VII degree of major key. Major key has two major seventh chords on I and IV degrees there are minor seventh chords on II, III and VI degrees while dominant 7 chord is on V. You must know and play them, music bases (above all) on these chords.