Not sure if this site is well known outside the niche community of researchers of late Russian Empire klezmer. It gives free access to streaming versions of the Ukrainian National Library's reissue CDs of wax cylinders of #klezmer, #Yiddish song, #nigunim, etc. from the 1910s through the 1930s. Most of these were recorded on folklore collecting expeditions in the Pale of Settlement or later in Soviet Ukraine and Belarus. Some very scratchy, fascinating stuff.
https://www.audio.ipri.kiev.ua/index.html
#WaxCylinder