Light colour such as blue,yewllol and maybe even pink lol imean laugh out loud if you don't know that means but a light couler to brighten the place up
My choices would be either a soft lavender, or a dull shade of aqua. Maybe even both, if you use one of them in your accessories. If your afraid to mix & match too much, go with a deeper shade of that silver gray in your carpet, and use the other colors for accents that you can change later on. I think a buttery yellow could work too, if your not afraid of using yellow. It's a tough color to live with after it's on your walls. But it is a good match up for gray. All depends on what colors you choose for your spread, curtains & accessories, too.