You can use any color color with white and black as an combination. If you are using light or dark gray with gray to make contrast.. Go for it. It also look very attractive.

If you have still any confusion, here are some popular website for Designers to choose color combinations.

Try these, it will help you.

http://paletton.com/#uid=1000u0kllllaFw0g0qFqFg0w0aF

http://www.colorcombos.com/black-and-white-color-schemes.html

http://www.colourlovers.com/web/palettes

https://color.adobe.com/create/color-wheel/?base=2&rule=Analogous&selected=3&name=My%20Color%20Theme&mode=rgb&rgbvalues=0,0.8415090030498504,1,0.91,0.8607153279948386,0.04550000000000004,1,0,0,0.05362198235978112,0.4820663032047579,0.91,0.7577276159272855,1,0.050000000000000044&swatchOrder=0,1,2,3,4

These are some popular website for Designers to choose color combinations. Try these, it will help you.https://color.adobe.com/create/color-wheel/