Come on, isn’t that awesome? 
(I haven’t managed to create an oil brush, but I managed to create something else
)
Alright so!
I’ve made those brushes:
One Kiki is cell-shaded, one is soft-shaded. They change colors
Download here: KikiBrushes.zip - Google Drive
Note: they don’t work on linear sRGB profile… As in, they work, but are ugly.