The GW+BSE approach has been benchmarked extensively for isolated molecules, for which high-level quantum chemistry reference data can be calculated. . Because the absorption edge is not abrupt, Tauc plots are typically used to extract the optical gap from absorption spectra. This can lead to some uncertainty in the experimental values. Here, if multiple experimental values are found for the same material, they are within 0.1 eV or less of each other in most cases. For the entries marked with *, we used the Tauc method to extract the optical gap from the experimental data because no value for the optical gap was reported in the paper. For the entries marked with **, there is a larger uncertainty in the optical gaps extracted using the Tauc method because the absorption edge does not decay to zero.