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 Beethoven Violin Sonata No. 5, 4 - Rondo: Allegro ma non troppo, Beethoven Violin Sonata No. 5, 1 - Allegro, Mozart Flute Quartet in D Major, 2 - Adagio