Is there a name for the style of the 'superhero' Russian statues? I can only find one example which is a statue of Yuri Gagarin But I have seen similar statues in documentaries and movies.
There was no special name for hero statues style, at least in the Soviet Union. "Socialist realism", according to Soviet official definition, was not a particular style but a general method (as they called it, but a more adequate translation would be "philosophy") in art. It applied to all art, not specially to hero statues. Here are some of the most famous examples: