The philosopher David Chalmers has created a website compiling the various kinds of zombies that can be found on the web. He’s interested in zombies because of the thought problems they present in terms of philosophy of mind, but he’s liberal minded and inclusive in his approach to zombies of all kinds on this site.
Zombies are hypothetical creatures of the sort that philosophers have been known to cherish. A zombie is physically identical to a normal human being, but completely lacks conscious experience. Zombies look and behave like the conscious beings that we know and love, but “all is dark inside.” There is nothing it is like to be a zombie.