You can use dyes for Nylon to add some color to the prints, but yeah Tough is blue to begin with so there’s only so much you can do. I have used a black dye from Ryt Dyes (in the DyeMore range) on Though parts in the past, and it makes the parts a bit less translucent and much darker, albeit there’s still some blue/green going on.
Recently another user reported good results with another acrylate dye which is very concentrated and usable directly on the liquid resin :