All Density Functional Theory (DFT) calculations are performed using Gaussian 16 . The meta-MD calculations and the RMSD-PP barrier estimates are performed with version 6.1.4 of the xtb program using the GFN2-xTB method. All structure-to-SMILES and structure-to-adjacency matrix (AC) (N atoms × N atoms dimensional matrix with elements either 1 or 0 depending on whether the atom-pair is bound or not) conversions are done using xyz2mol. The low-barrier dataset used in this study is extracted from the dataset created by Grambow et al. The reactants in the Grambow dataset consists of all molecules in the GDB-7 dataset with less than seven heavy atoms plus ca. 430 randomly selected molecules with seven heavy atoms. Reactions and the corresponding transition states (TSs) are located by performing several hundred single-ended growing string method (GSM ) searches from each reactant at the B97-D3/def2-mSVP level of theory, followed by TS refinement at the ωB97X-D3/def2-TZVP level of theory. The result is 16,365 and 11,961 unimolecular reaction barriers at the B97-D3/def2-mSVP and ωB97X-D3/def2-TZVP level of theory, respectively. The corresponding number of low-barrier reactions with barriers below 30 kcal/mol is 199 and 30, involving 163 (Figure ) and 27 different reactants, respectively. We would thus expect that applying our meta-MD search to these 163 reactants (Figure ) should identify these 30 reactions (Table ) if we use ωB97X-D3/def2-TZVP for the DFT refinement.