I don't think everything goes with black trousers. For example, I do not prefer pastels with black. I like very saturated colours with black. And when I wear a bright like red, yellow, citron, orange, fuchsia or emerald with black - I usually wear white along with the combination so that the look stays crisp. This is not essential - I'm just personally big on crisp looks.
I really like cobalt blue and ink blue with black. Also like most shades of brown with black. I sometimes like grey with black (usually I prefer it when there is white in that mix for myself). And of course, cream and white are no-brainers.
I love metallics with black.
I like black on black too but the outfit MUST be textured.
I hope that helps!