This is a somewhat rare assortment of files from the Big Children's Choir ( Большой детский хор ). They are most known for their rendition of the song Прекрасное далёко (Wondrous Future), a song the children sing about a future that they hope will not be cruel to them and has since become a sort of eulogy for the USSR's collapse in Russia. 
This playlist includes my favorite songs from the Big Children's Choir, but you can download all (250+) of the files in the link provided on the TankieTube playlist or my comment on Wondrous Future.
I have transliterated all the Russian text to be more readable to English viewers, but the original files are unedited and contain their Russian names for easier searching.
Great work! I'll sticky it to the homepage soon.