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 Jean-Philippe Rameau - Suite in D major (Pièces de Clavessin 1724), Leoš Janáček - Sinfonietta, Arnold Schönberg - String Quartet No. 3