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 myVST Demo: Efthimia Electronic Organ V1.4, myVST Demo: EP 2008 electric piano, myVST Demo: Hahaha CS33 to v2.0