There are many mediums you can use on polymer clay, the most common being soft pastels.
I’m not very fond of them because for me they seem to be to hard.
I prefer to use make up. And before you say eye shadow is all glittery, I’ll say you can get matt make up.
I got this pallet from Dischem the other day, its bright beautiful colors in a matt finish that is gorgeous. Way better than pastels. The pallet only cost about R80 I got it for nothing because I used my rewards points.
Score all the way.
So keep an eye out for things that you can use with your clay and other crafts. You never know when you might find something in the most unusual of places.