A blending pencil, that smudges colours together if you want to.
Kirstie Adams commented
I believe that the Apple version has these features already, but it would be great to see them come to Android too! I use this app loads and love it, but I get frustrated when I'm having to blend using the colour picker and a low opacity brush. Keep up the good work!
Please add another way to pick colours that would have them all in one place as opposed to us having to scroll through 20 palettes looking for a colour to use. If you could add it for even the paying members that would be great. I've seen several apps with very simple colour wheels along side a tonal slider like the one you have already. A saturation slider would be nice too.