  A gauge U(1) framework was established in 2002 to extend the supersymmetric
standard model. It has many possible realizations. Whereas all have the
necessary and sufficient ingredients to explain the possible 750 GeV diphoton
excess, observed recently by the ATLAS Collaboration at the Large Hadron
Collider (LHC), they differ in other essential aspects. A compendium of such
models is discussed.
