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 Cristofori Piano: Sonata K.9 by Domenico Scarlatti, The Roentgens' Berlin Secretary Cabinet, Stradivari violin, "The Antonius," played by Eric Grossman (full version)