If we are just talking about the Holodomor, I have seen estimates ranging 6 million to 13 million.
Genrikh Yagoda, a name unfamiliar to the masses, don't let this Hitler mustache look alike fool you, he is no saint towards the human races. Genrikh Yagoda was a communist mass murderer in the communist controlled Soviet Union. He was responsible of the deaths up to 10 million people and the 5 million sent to prison camps (Gulags).
he is said to have killed 20000 or more himself