To enable rapid and cost-effective testing of predictions, CACHE will establish a well-defined and robust "Core" Make-on-Demand (MoD) virtual library comprising compounds that are readily accessible from commercial vendors, at reasonable cost. A combination of Enamine REAL * and ZINC20 might comprise the core of this library. CACHE will annotate compounds in the library with predicted physical properties (e.g., cLogP, PSA, Fsp3, etc.) that will be assessed in the success criteria (see next section). The aim is to enable each participant to select individual subsets and/or apply relevant filtering which he/she sees fit, while ensuring any such pre-filtering or sub-set restrictions can be accounted for in any subsequent evaluation and comparison of approaches. CACHE will also create "Subsets" within the initial library as may be required to account for the needs of specific CACHE participants (e.g., a 1% diversity set or a 10% diversity set might be preferred when examining computationally intensive approaches, etc.). The libraries will evolve, adding more compounds as they become commercially available or accessible, and creating additional library subsets as feedback on the performance is collected.