The computational cost of SISSO-generated models varies depending on the number and type of primary features they contain. The relative cost of each primary feature was evaluated in a similar manner to Ref. , relative to the calculation of the single molecule gap, Gap S , whose cost is the lowest of all the primary features. The computer time required to calculate Gap S was assigned a value of 1 cost unit and the cost of other features is given in Table as multiples of that unit. The cost of all the primary features has been updated to account for new developments in the latest version of FHI-aims. In particular, the many-body dispersion (MBD) calculation has become significantly more efficient than in older versions of the code. In addition, we averaged the cost over the 10 structures in the validation set, rather than picking one system of average size, as in Ref. . The cost of each SISSO model was evaluated by summing over the costs of all the primary features included in it. The cost of features that appear in the model more than once was counted only once. The cost of features that do not require additional calculations was also counted only once. For example, the crystal band gap, Gap C , valence band dispersion, V B C disp , and conduction band dispersion, CB C disp , are ex-tracted from the same band structure calculation. Therefore, if two or more of them are included in a SISSO model the cost is counted only once.