I believe the Suave Naturals conditioner line is silicone free. It is CG. I use it the "Coconut" one to Co-wash and sometimes as a LI. I've used it while color treating my hair. It seems to work well under most conditioners, for me anyway.
I do also use a conditioner by Kenra, which is labeled specifically for color-treated hair. It's much more expensive than SNs, but it's also CG. It contains keratin protein, if that's info that's helpful.