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 Let's Learn to Play EU3: Divine Wind Part 7 (How PU's work, why they work, and why you should), Let's Learn to Play EU3: Divine Wind Part 9 (Colonies and Quiet)