If you are interested in learning more about chords, the psrtutorial site has a series of lessons on "The Secrets of Chords and Chord Progressions." The series currently covers all the chords in 19 lessons spread out over 3 "classes." Another 20 lessons or so will be added as time goes on to cover Chrord Progressions. However, at a lesson a week, anyone starting on this journey has many months of material available. Here is a direct link:
http://psrtutorial.com/Resources/R_ChordSecrets/r_chordsecrets.html