``Slim'' benchmark sets for faster method development

The construction of large benchmark sets has accelerated advancement of quantum chemistry methods, especially in density functional theory and lower-cost methods. However, these large benchmark sets can be unsuitable for cutting-edge method development, because research codes developed for fundamentally new approaches are often inefficient and may consequently struggle to handle large molecules. Here, we introduce \texttt{Slim} benchmark sets that are designed to `summarize' the statistics of larger counterparts, but have the advantage that molecules are restricted in size (to five, 16 and 20 atoms) and may therefore be treated by inefficient implementations. They thereby allow data-driven methodologies to be exploited in the early stages of cutting-edge method development.