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 Credo III Gregorian Chant at 6-6-11 Latin High Mass sung by Latin Schola of Saint John the Baptist, " Creator Alme Siderum " Gregorian Chant Advent Medieval Organum by Schola Cantorum