High-quality spectral reference libraries are important for algorithm development and identification of diagnostic optical characteristics of target objects in earth observation monitoring applications. We present additional measurements conducted using hyperspectral sensor technologies in a laboratory and an outdoor setting to further extend high-quality data as well as diversity in available open-access spectral reference libraries. These observations involved gathering hyperspectral single-pixel-point and multipixel optical properties of a diverse set of plastic materials (e.g., ropes, nets, packaging, and personal protective equipment). Measurements of COVID-19 personal protective equipment were conducted to also further expand spectral reference datasets that could be useful in remote sensing the mismanaged waste in the natural environment that was generated during the pandemic. The sample set consisted of virgin polymers and ocean weathered and artificially biofouled objects of varying apparent colors, shapes, forms, thicknesses, and opacity. A Spectral Evolution spectroradiometer was used to collect hyperspectral reflectance single-pixel-point information from 280 to 2500 nm. Imaging was also performed using a Specim IQ hyperspectral camera from 400 to 1000 nm. Sampling underwater was completed in intervals of 0.005–0.215 m within a depth range covering 0.005–0.715 m. All optical measurements are available in open access for the laboratory experiment via https://doi.org/10.4121/769cc482-b104-4927-a94b-b16f6618c3b3 (de Vries and Garaba, 2023) and an outdoor campaign involving the biofouling samples via https://doi.org/10.4121/7c53b72a-be97-478b-9288-ff9c850de64b (de Vries et al., 2023).