The valence isoelectronic series of the known PAuP5-, SAuS3-, and ClAuCl- is continued to the predicted gas-phase or matrix species RgAuRg(+), where Rg is a rare gas. The diatomic species AuRg(+) are also studied. Quasirelativistic pseudopotential studies, at levels up to CCSD(T), including a counterpoise correction, predict AuXe bond energies of up to 0.9 eV and bond lengths of about 276 pm, close to the sum of covalent radii. Substantial electron transfer from Xe to Au+ occurs. Over half of the Au-Xe bond energy comes from relativistic effects. The bonds to Rg = Ar and Kr are weaker than those to Rg = Xe, while He and Ne form weak complexes. At large distances the AuXe+ potential curve coincides with that of AuXe-.