Swatches & brush for Precreate is the best tool for creating and generating tool, helping you to create color palette with different algorithm, includes:
Analogous
Triad
Monochromatic
Complementary

It also allows you to generate a color scheme with 10 elements, you can simply just pick one color and then press the generate button.

Furthermore, it can be used to extract dominant colors from an image and then generate the color palette with just a touch.

The generated color palette then can be exported to .swatches extension and then import directly to Procreate and ready for use.

You are also offers a list of beautiful brushes that can help you boost your creativity, create a perfect drawing.