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 Sibelius 7 Sounds - 3. Winds, Orchestration Tip: Tchaikovsky's Interlocking Phrasing, Orchestration Book Club: Lovelock's Elements of Orchestral Arrangement