• Individuals: In this work, we stand on the shoulders of giants in the force field development community, and it would be impossible to provide a complete list of all those whose work we have benefited from. However, we are particularly indebted to the AMBER force field community, from which we derived the initial small molecule force fields, which provided the starting point for this work. We thank the Open Force Field Consortium for funding, including our industry partners as listed at the Open Force Field website. We thank the Open Force Field Consortium and Initiative for financial and scientific support, and the Open Molecular Software Foundation (OMSF) for its support of the Open Force Field Initiative. Particularly, we gratefully acknowledge Karmen Condic-Jurkic for helpful discussions, along with all current and former members of the Open Force Field Initiative and the Open Force Field Scientific Advisory Board. • Grants: We thank the National Institutes of Health (NIGMS R01GM132386) for funding longer term aspects of this initiative. M.K.G. acknowledges funding from the National Institute of General Medical Sciences (GM061300