A more detailed inspection of the 311 Q complete entries in the library of reaction patterns revealed that a subset of 20 rules disproportionately accounts for 80% of all cataloged reactions, as depicted in Figure . The two most prominent rules are amide formation (Rule 8 ) and amine alkylation (Rule 2 ), as illustrated in Figs. and, respectively. Detailed descriptions of these 20 rules are provided in Table . The entire library of rules is available in the Supplementary File 3.