You can use other shades of gray and some shades of cream or ivory. Try getting some of the paint sample cards from the store and see what paint looks best with your carpeting, this will give you some idea how they will look together with the lighting and sunlight in the room.
I think a light cream on your walls would look great, and it would look good with what ever color your furniture is.
A light silver color on the wall will go well with a grey carpet.
With gray I like red, coral, teal and navy blue.
White, cream, light tan, pink, powder blue, stuff like that. Hope this helps, good luck to you.
If you don't want white, you can use an ivory shade. It is not stark white, but it allows for many types and colors of furniture to go with the gray carpet. A very, very pale dove gray can be used also.
Depends what style your going for...modern look would add black and white, softer look you could use yellow, blue also, but be careful use swatches before you buy anything, you could make some costly mistakes with blue.