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 Béla Bartok - Music for strings, percussion and celesta, The Lark Ascending - Ralph Vaughan Williams - Part 1, Arensky - Concerto pour violon / for Violin, Opus 54