There is also charcoal bread, which is black.
Some of the international franchises of McDonald's in Japan also offer black buns colored with squid ink on a limited regional basis, too. For a few years Burger King offered a black bun here in the US around Halloween as a promotional gimmick. However, the side effect of the dye turning one's poo green resulted in a commercial failure once word spread.
Anyway, as Piscean mentioned, none of those are what we normally think of as black bread.
What we call '
black' is really just a dark brown in most cases. Some recipes do call for black cocoa, and of course a darker molasses will skew the color closer towards an actual black. Unless there are additives to purposely make it darker (squid ink, cocoa, charcoal (?!:shock
, black molasses, etc.) it's really just a dark brown.
It's darker enough from something like whole wheat to merit a new descriptive category, and I suppose "really dark brown bread" wasn't catchy enough.