Black and Brown:
We're talking about a deeper brown here, because lighter shades of brown such as tan are of course acceptable. A darker brown is completely acceptable when paired with black, just in moderation. For example here are some examples of how to do black and a darker brown right :
Although not the brightest color combination, navy blue and black actually look great when paired together correctly. If you don't want to take my word for it, here's some proof:
Here's the thing, I couldn't find any pictures of the colors working well together in an outfit because, well they just don't. This is the combo that just can't happen. Some things just don't compliment each other well, and when it comes to colors, those things are grey and brown. Light brown, dark brown, tan.. it just isn't going to happen.
Well I hope that helped to clear up some confusion!
Stay Classy :)