I'm a researcher at the Music Technology group who works on freesound ( https://www.upf.edu/web/mtg ) We also maintain Freesound labs, which lists a lot of projects and research made using content from freesound: https://labs.freesound.org/ FSD50k is our hand-curated dataset of sounds designed for research in sound and event recognition tasks https://zenodo.org/record/4060432#.X3xrgi8RqL4 , http://dcase.community/cha…
What a resource. Here's a random sound: https://freesound.org/people/Bosk1/sounds/144083/