In this class we include submissions where fully anharmonic calculations (i.e., including all degrees of freedom in the cluster) were carried out. Interestingly, none of these submissions made its way into the top 5, meaning the submissions with the lowest RMSD. The worst performing submission under this category was FA2, with large deviations for the PYR and THT systems (90 and 86 cm -1 respectively), then abruptly falling below 40 cm -1 deviations. The values are estimated on the basis of VPT2, making use of the PBE0-D3(BJ)/aug-cc-pVTZ level of theory. We already noted that the PBE0 was the worst performing functional under the PH category (PH2). The anharmonic corrections have a relatively small impact, reducing the RMSD values by less than 10 cm -1 . We observe no issues in the minima chosen for the calculations. The problems can be foremost linked to the choice of functional. The same authors submitted the dataset FA4, whereby the CCSD-F12/aug-cc-pVDZ harmonic values are corrected by the anharmonic difference estimated at the PBE0-D3(BJ)/aug-cc-pVTZ level (VPT2 vs harmonic). The errors are greatly reduced in the latter variant. Comparison to FA2 on the basis of Fig. should be careful. The FA2 set features the TFE value, which is an extremely small shift, while FA4 does not. Overall, the submissions which include TFE (with the right minimum) are somewhat favored by the metric we use, based on absolute errors, not relative. FA5 is also from the same group, with the same anharmonic corrections, but using MP2-F12/aug-cc-pVDZ harmonic values. The results are of comparable quality to those obtained with CCSD-F12 normal modes (FA4). The FA3 set consists of B3LYP-D3(BJ)/def2-TZVP VPT2 anharmonic frequencies. Again the largest deviations are found for the PYR and THT systems. Once these two are removed from the analysis, the RMSD falls below 30 cm -1 . It could be of interest in a further publication to revisit these systems and understand in further depth the shortcomings of VPT2. We note in passing that the affordable combination of harmonic CCSD(T)-F12a/cc-pVTZ-F12 with VPT2 at MP2/aug-cc-pVTZ level, which was explored for FAH when analysing the hydrate anharmonic resonance in ketone hydrates, made a blind prediction which now turns out to be within less than 10 cm -1 of experiment. This wave function based composite model belongs to the class of fully anharmonic methods and should be explored for the full test set in the future.