I am finding that the deep browns such as chocolate, coffee, umber, unpolished amber, hazelnut & mahogany work well with both light grays and dark grays.
I love gray:
ash, granite, oyster, pearly shades of dove, slate and smoky silvery greys.
Mix these color combos by pairing say a brown pant, with grey cardigans and underpinnings for a fresh and modern look for fall. Or reverse.
I cannot take credit for this idea folks, it came from my employer. Eileen Fisher, Inc. creative types in our visual merchandising department started showing these two color combos together in a series of creative in store outfits on mannequins. Very cool.
The plus it all this goes with my hair color!