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 Seigneur je crie vers Toi - chant byzantin - ton 1, Tropario de Pentecostés - canto bizantino, Polyeleos from Matins - Carpathian chant (English)