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 Fiddle Fest-Heim Middle & North HS Orchestras -Side by Side-3-22-2011, I Can Feel The Rhythm-Casey Middle 7th & 8th grade Chorus-5/24/2012