In the previous post, we touched on the commonly used color scheming techniques, those being the complementary, split complementary and the analogous color theories. I had to make a second post dedicated to color harmony, just because one post wasn’t enough to cover all of it.
Color harmony has a wide spread of theories, but the common five is what is usually made use of. I have yet to give an actual definition of color harmony. So according to Rikard, the creator of ZevenDesign, it is “the theory of combining colors in a fashion that is harmonious to the eyes” (Rodin, 2015, para. 1).
Rikard explains in the same article that a key color is needed for every color scheme you choose, no matter what it is. This is because the key color is the most important color of your piece or design, and is usually the most prominent color as compared to everything else (Rodin, 2015, para. 5).
In my painting of the piranha plant from Nintendo’s franchise (fig .1), you can see that the main key color is red, accented by the green and yellow.
Moving back on topic, there are two other color theories I didn’t get to talk on previously, one of them being the triadic color scheme. What makes this color theory work well despite being less flexible is because of the colors being able to be vibrant and lively even if its unsaturated (Tiger Color, para. 3).
I sometimes make use of this (fig. 2), because having three strong colors give a solid image and color scheme in mind without having to think about other outside colors. Each color also give off their own mood, so depending on your key color, it will affect your art’s subtle meaning significantly, using the other colors as an accent for the main mood.
Back to color harmony, the last which I also use at times is the tetradic color scheme, also known as double complementary. This color harmony scheme makes use of four colors, two pairs 
of complementary colors. This works well because of how easy it is to balance out warm and cool colors with the palette you choose with this color scheme. It also gives you a rich color palette due to two pairs of complementaries working together (Tiger Color, para. 5).
I made use of this in one of my commissions, drawing Bowsette (slideshow below), the key colors being on the warm side, with the two cool colors being used as accents. The second commission also uses this scheme, but this time the key colors are on the cool side of the spectrum, using more purples and having oranges as the accent (slideshow below).
That covers all commonly used color theories, and how they could be possibly used. I hope this has helped you some.
References
Rodin, R. (2015). Color Harmony: Why Hulk Wears Purple Pants. Retrieved from
https://zevendesign.com/color-harmony-hulk-wears-purple-pants/
TigerColor. (n.d.). Color Harmonies – Basic Techniques for Combining Colors. Retrieved
from http://www.tigercolor.com/color-lab/color-theory/color-harmonies.htm
Images
TigerColor. (n.d.). Color Wheels. Retrieved from
http://www.tigercolor.com/color-lab/color-theory/color-harmonies.htm
Burfles' Art and Talks 