The built-in reference data for chemical compounds relevant to fragment-based assembly are stored in the Resources sub-package. This sub-package provides numerous functions to query compounds, load existing data or read new data from files, add molecules to the reference dataset, as well as save datasets to files. The default reference data is a subset of the Protein-Data-Bank's Component Dictionary (PDBCD), containing a chosen selection of 7,630 molecules out of the nearly 40,000 available. To facilitate efficient access, the reference data is further categorized into five individually loadable datasets: small molecules, amino acids, nucleotides, sugars, and lipids. Additionally, users can load their own custom datasets in the mmCIF format for further flexibility. Beyond fragment data, we also included a selection of molecular linkages derived from CHARMM topology files (Patches). Custom linkage defined in the CHARMM topology format can also be imported into the reference dataset. Figure provides a graphical summary of the built-in reference data. For user convenience, all core functionalities of the Resources sub-package are automatically imported upon loading the main BuildAMol library. This eliminates the need for manual interaction with the sub-package itself in most use cases.