Despite this success, there remains a gap between the small, rigid molecules in QM9 and technologically or pharmaceutically relevant compounds, which are often larger and much more flexible. Furthermore, the target properties of molecular discovery are in practice seldom simple electronic properties that are directly accessible through single-point DFT calculations. Instead, complex properties like the bulk electronic conductivity, pharmacological or catalytic activity of a molecule are ultimately of interest. Unfortunately, these are extremely complicated to rigorously simulate even for a single molecule. In high-throughput virtual screening (HTVS) studies, it has therefore become common to focus on simplified descriptors that are known to correlate with the property of interest. Such descriptors include, e.g., the binding energy of a key intermediate in catalysis or the internal reorganization energy (λ) in molecular electronics.