I Have Grey And White Marble Porcelain Floor And Gray Tub Bath And Sink I Painted The Upper Part Of The Wall White With A Light Gray Bottom Wall With A White Chair Rail I Am Looking For Curtains That Would Go Good With These Colors, Can You Help?

Grey is neutral so most colors go with it. White, black, those work well of course.
Red, blue...that depends on what you want to do with it.
For a summer cottage look, try white, yellow or grey so that your windows blend with the wall.
If you want a muted tone, try ash blue. A blue with a hint of grey, for a beach-side look, or white.
Or if you want to contrast, then use stronger color, try black, deep navy or a duller nautical blue, or red. Nautical colors work very well with grey. Just think of the beach! Or for more modern, use black.