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 Jiri Slavik with a Pizzicato Improvisation on the Upright B, April Verch Fiddle Lesson on Left Hand Ornamentation, D'Addario: Jazz Violinist Ben Holder on Pro•Arté Strings