I think they are quite many, especially from the late USSR.
- Many science fiction cartoons: Контакт, Полигон (BTW about violence), Контракт etc. etc.
- Cartoons were the most free art area for experiments. Will you tell me that Ежик в тумане was intended for children? ORLY?
They can say "This is for children" and produce all kinds of psychodelic insanity.
- Aesopian language, humor, satire... Великолепный Гоша, Фильм-фильм-фильм, Остров сокровищ... For children? Well... for children too.