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 Line 6 M13 Ambient Guitar / Pad Sound, Strymon Flint - 80's Reverb and Tremolo vs Fulltone Supa-Trem, Silicon Fuzz + Delay - violin test