Building on this success, we constructed a database called the "RSE Atlas" containing 16,905 single-ring molecules. Ring systems were extracted from commercially available compounds (Sigma-Aldrich, Enamine, WuXi, MolPort) and literature-reported building blocks and reagents (PubChem, SureChEMBL). These rings represent the majority of known carbocycles and heterocycles, including an extended set of elements like S, P, Se, B, and I. The ring sizes range from 3 to 9.