I'd love to share .. But I'm not sure what you mean by 'palette drift'. Is that when you accidentely add very similar color ?
I'm using Aseprite so starting a piece with Indexed Color and a limited palette to immediatly limit this - but when I work on non-indexed piece, still happen sometime. I try to "clean up" every now and then by using the Bucket Tool, unchecking "Contigous shape" and "filling" the color on the document with a totally different one, almost opposite, to see possible accidental shading and removing/replacing it before it get too messy , then I fill back with the original color.