First of all, scrap the idea that navy and black don't go together. They do. You just have to be intentional about it, and choose a brighter navy, not one that looks like it might be mistaken for black.
Navy can be used as a true basic -- gray goes great with it as does cream, but other good more unusual options are pale, ballerina pink -- think pale pink merino shell, navy pants. Also, if you are a bit braves, other blues like aqua and turquoise look great with navy.
