screens and electronics, the desire and necessity for reliable ptype TCMs is increasing inexorably. This has led to an explosion in new avenues of p-type TCM research, with database-screening and machine-learning driven discovery bringing countless potential materials to the attention of the community. Non-oxides are particularly attractive candidates as p-type TCMs because the valence orbitals on the anion tend to be more diffuse than the oxygen 2p orbitals at the heart of more traditional materials, and often form valence band maxima with greater dispersion. This trend was quantified by Varley and co-workers in 2017, where they surveyed 30, 000 structures on the Materials Project, finding that phosphides had a median hole effective mass around 5m e lower than that of oxides. This is quite a significant difference, suggesting that phosphides, and indeed other non-oxides, are an exciting class of materials for high hole mobility applications.