tion was incrementally added to each angular symmetry in the cc-pVnZ-PP-F12-OptRI ABS, and then discarded if the resulting change in the error metrics was negligible. The number of functions retained depended on both the zeta level of the orbital basis and which row of the periodic table the element belonged to. The latter could perhaps have been anticipated as the composition of the parent cc-pVnZ-PP-F12-OptRI sets also varies with row. Final compositions of the resulting aug-cc-pVnZ-PP-F12-OptRI sets are presented in the Supplementary Material, along with the optimized exponents. For the 4p elements, DZ was augmented with 1g function and TZ with 1i. 5p required 1f at DZ level and 1f1g1h1i at TZ, while 6p needed 1h at DZ and 1i at TZ. For all three rows, the QZ parent set was augmented with 1h1i functions. The exponents for the group 18 elements were determined by extrapolation of the optimized exponents for other elements in the same row, in a similar fashion as for the orbital basis sets. The functional form used for this extrapolation is given in the Supplementary Material.