videos in AudioSet
A list of about a million ten-second YouTube clips, each labelled with the sounds in it, that Google published in 2017. Labs use it to train and test general audio and music models.
Including A Mendelssohn - Two violin and piano trio op.76 - 4 Finale: Sostenuto, allegro non troppo, A Mendelssohn - Two violin and piano trio op.76 - 1 Allegro