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 Death and Transfiguration (Tod und Verklarung), by Richard Strauss - pt.2, 'Fantasia on a theme by Thomas Tallis', by Ralph Vaughan Williams (1872-1958)