Remote sensing of marine debris is limited by the lack of a unifying spectral reference library to support algorithm development. The open-access MArine Debris hyperspectral reference Library collection (MADLib), with 24889 hyperspectral reflectances from 3032 diverse debris samples, is a well-curated database of representative spectra. We describe the available data, discuss gaps, and propose improved metadata schemes to expand the MADLIB collection and support sensor and algorithm development.