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 Shadow Over Aldrheim - Magicka - Cello Quintet Cover (Sheet Music Linked), Time's Scar - Chrono Cross - Classical Guitar Duet, Fake Wings - .hack//SIGN - Cello/Classical Guitar Cover (Free Sheet Music Linked)