Maj7, Min7, Dom7, Min7b5, Dom7sus4, 7#5, Dim7, Maj6, Min6, Min9, 9, 7b9, 7#9, 13– at least 2 forms for each. These chord forms are in all fourth tuning
Improvising over a simple chord is much more fun than you might think. The simpler the chord is, the more improvisational options are available. Why? Because you have less chord