  We consider 3D consistent systems of six independent quad-equations assigned
to the faces of a cube. The well-known classification of 3D consistent
quad-equations, the so-called ABS-list, is included in this situation. The
extension of these equations to the whole lattice Z^3 is possible by reflecting
the cubes. For every quad-equation we will give at least one system included
leading to a B\"acklund transformation and a zero-curvature representation
which means that they are integrable.
