The remaining 15,837 complexes were classified based on metal identity, OS, coordination number, coordination geometry, and composition of the metal-coordinating atoms, resulting in 1,633 distinct groups of complexes that share the aforementioned characteristics. We then performed stratified sampling among those groups to construct a dataset of 2,261 complexes where each group is represented (see section S1 in the SI for further details regarding dataset construction and curation, and section S2 for a discussion on the excluded complexes).