It was one of my projects, maybe you could use it.
Simple to use. Select the layer (wheel) you want to use by making visible and hide the other layer wheel.

Press Shift + R to rotate the Wheel, keep holding down the Shift key while turn the layer. Pretty simple
to work. Then you can use your eye dropper to change your colors. The chart is on a 10"x10" image.
The blending modes is a 10% stepping curve for dark and light tone.

Very clever. Is it any different to this though, which gimp already has?

The straight line takes you to the colour your after and the circle to the lightness or darkness of that colour - both of which can be moved by your cursor. Your foreground colour will change automatically to where you have your circle set. However if you want a different colour in this triangle you can use the colour picker provided in the tool options for this to change your foreground colour.

You get to select from 1 to four colors at a time in the proper color style; but the colors are fixed.
see the names of each color wheel. It was meant so I wouldn't have to guest about what color
idea I wanted to use before going a website and getting better tones and colors.


1st row
A tetrad color scheme is a color palette that consists of four colors arranged in two complementary pairs. This scheme is created by selecting colors that are evenly spaced around the color wheel, resulting in a vibrant and dynamic palette. Tetrad color schemes can add visual interest and balance to designs, making them effective for various applications in art and design.

2nd & 3rd row
A triad color scheme is a color harmony that uses three colors positioned at equal distances from each other on the color wheel, forming an equilateral triangle. This arrangement creates a dynamic and visually appealing combination that maintains balance while providing high contrast. The most common examples of triadic color schemes include:
Primary Colors: Red, Yellow, Blue
or
Secondary Colors: Orange, Green, Purple

Nice one.
Thank you.