For each chemical combination, we used the pymatgen package to find the most likely ionic substitutions, capping them at 15 per system. We used the default log probability threshold of 0.001, where the false positive rate for substitution in the ICSD test set was near zero and the true positive rate was near 50%. We then collected Materials Project database entries for the substituted combinations (eg. Cs 2 NaNdF 6 for Nd 3+ -Cs + -Na + -F -). We substituted the desired ion(s) into these entries and any of their polymorphs.