ESR spectroscopy is an important method for characterizing radicals. However, the isotropic hyperfine coupling constants are difficult to calculate. The effects of solvent and molecular vibration are often not negligible. We provide benchmark values near the full Cl, complete basis set limit for nonvibrating H-., H-2(+.), and H-4(+.) in the gas phase. These are used to judge the performance of already existing and newly constructed basis sets. The new (aug-)cc-pVXZ-t5s basis sets are superior to previous basis sets. They have average errors between -0.4 and -0.1% of the reference values. The rms deviation from the average error is less than 0.2%. Only extreme contraction significantly increases the errors. Larger valence basis sets improve the accuracy.