The third set of molecules was obtained by filtering DrugBank, a free database of drug and drug-like molecules. Molecules with fewer than three or more than 100 heavy atoms were removed, as were any molecules with metals or metalloids. Next, the molecules were assigned parm99/parm@Frosst atom types, and any molecule that could not be typed was removed. The molecules were then also typed with smirnoff99Frosst version 1.0.5 and any molecules assigned a generic parameter, for example any bond ("[*:1]∼[*:2]"), were also removed. Finally, we selected a reduced set of compounds that include all atom and fragment types in the reference force fields used in DrugBank after this filtering. The final set, termed MiniDrugBank, has 371 molecules containing 15,678 atoms, and is available separately on GitHub ().