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 Ennio Morricone - The Ecstasy of Gold (Quartet cover - Violin, Viola, Contrabass and Piano), Metallica - Nothing Else Matters (Quartet cover - Violin, Flute, Contrabass and Piano)