Here is my “Commercial Chord System” for keyboard players, free for you to download and study. There are currently three chapters starting with basic major and minor chords, progressing into dominant 7th, 9ths, 11ths, and 13ths.
The main purpose of this system is for keyboard players who would like to play in a group such as a worship band, or accompany singers and instrumentalists.
Please contact me to let me know if you’ve enjoyed using this resource. I hope to receive a good response and continue offering more resources on this subject.