For all force fields trained above, a few filtering steps were common. Molecules with changes in connectivity between initial and final structures after geometry optimization were filtered out from the training targets. Most of these include molecules with an intramolecular proton transfer occurring during the optimization. Additionally, for torsion-profile targets, molecules with strong intramolecular hydrogen bonds were excluded based on Baker-Hubbard criteria as implemented in MDTraj. Molecules with intramolecular hydrogen bonds were excluded to avoid strong internal interactions affecting the torsion fitting and impairing the transferability of torsions, which we do not design to capture hydrogen bonding.