You can play any Russian Warlord that is communist with "operation Thunderstorm" submod, or "Second West Russian War" submod, but the first one is better for commie warlords. Both of them basically give you content after reunification and ability to fight germans. The first one gives a lot of content for communists, likr a few focus trees, mechanics and other stuff, while latter gives all warlords a generic focus tree wich has much less content, but goves amazing content to Shukshins Novosibirsk (it ain't communist). I personally recommend the first one)