The palette is extracted from the frog images. It's only meant as areference, and can change later. Hot pink (255, 0, 255) is used to fill the gaps.

[blank], mid highlight, high highlight
low base, mid base, high base
[blank], mid shadow, high shadow
inner cheek
tongue outline, tongue shadow, tongue base
leather shadow, leather base, leather hightlight
wood shadow, wood base, wood highlight
sharp shadow, sharp base, [blank]
dull shadow, dull base, [blank]
frog outline, metal outline, wood outline