Gradients that can be used to create a gummy-like shading effect, inspired by the stylised shading some artists do on paws.
Start by shading you object as you would normally.

You can then use gradient maps to apply the gradient.

If you want to use your own colors, you can use the grayscale option on 'Brightness' blending mode above a color layer. (Demonstrated with the paw pads in the image)

I recommend editing the shading manually after you apply it!