Figured that we needed a thread for classic theatrical cartoons already available online. Obviously the lifespan of anything on YouTube is temporary so some of these videos may need replaced later. Feel free to contribute more. I will try my best to provide as much information on these.
Covered this one already here: http://forums.tcm.com/topic/36026-russian-soviet-films/?tab=comments#comment-1618034
Lev i Byk (The Lion And The Ox)
Soviet Union: Soyuzmultfilm