Blacks and the various flavours of oriental black (Eskimo, abo, etc). But even that depends on the mix of black. Pure negress is a no no. But very light darkies are a maybe. Marriage is basically limited to europe.
Abos, purebred Pacific Islanders, Jews, purebred Native Americans, South Asians, most Arabs (except for maybe North African Arab-Berbers or Coptic Arabs), Gyppos, Blacks, Mulattoes, Quadroons, Octoroons, Hexadecaroons, Southeast Asians, East Asians, Hapas, Northern Asians, Central Asians, probably more groups.