Here you find a library of spectral curves/signatures (from Sentinel-2) of several classes, developed under H2020 LABPLAS project. The library is designed to support the development of models for the detection of marine plastics in Sentinel-2 satelite images. The library includes spectral signatures of floating marine plastic (from artifical plastic targets and pollution events), as well as other features (e.g. clouds, marine water, foam/spume filaments, breaking-waves, turbid waters, aquaculture structures, phytoplankton blooms). In the H2020 LABPLAS project, the present library was used in conjunction with a publicly-available library called MARIDA. The present library is fully compatible with MARIDA, and therefore both libraries (this and MARIDA) can be easily merged. Hence, the present library adds additional spectral signatures to MARIDA, creating a larger and more comprehensive library for the satellite detection of marine plastics in Sentinel-2. The reflectances are Rayleigh-corrected reflectance (Rrc), which was done with ACOLITE processor on the original L1C Sentinel-2 data (as in MARIDA). The total number of spectral curves is 115,410.