Most of my Second World War 20mm collection for the European theatre focusses on the later stages of the war from late 1942 onwards and so that's reflected in the models and figures I own. The Russians are no different and though I do have a few of their earlier tanks, like this BT-7 in the picture below, for this post I'll focus on those that are likely to be seen in the later stages of the war.
In which case I suppose any talk of Russian tanks might as well start with the ubiquitous T-34. If you only ever have one Russian tank in your collection you probably can't go far wrong with one of these. The set from the Plastic Soldier Company includes three models but has two sets of turrets for each body so that you can make up the earlier T-34 with the 76mm gun or the later models with the 85mm gun. This is extremely handy, as in effect the set gives you six possible tank options. With that in mind I made up turrets for both models and can interchange them as I need.
Here's the 76mm version with a crew figure from AB.
There are plenty of these to be found in museums given they were still produced after the war and were used in the Arab/Israeli Wars, Korea and Vietnam, amongst others.
This one is in the Military Museum in Beijing.
I had an unmade kit of the old 1/76 Airfix version of the T34 and thought it would make the good base for a model of a wreck. It could be used as scatter terrain or in a campaign if we replay over a table where a tank has been destroyed. I scratch built the interior and you can follow that build in more detail in this post.
The KV1 was designed and manufactured around the same period as the T-34 and competed to be the main battle tank of the Red Army. Like the T-34 it carried the 76mm gun and had similar armour. It suffered from early mechanical issues and performance, although these were later resolved. The design was eventually dropped when the T-34 proved to be capable of doing all that the KV-1 could do but could be produced faster and cheaper. The KV design was not totally redundant and the chassis went on to be used for the later IS tanks.
This is the version from Pegasus Hobbies and much like the T-34 from PSC the set of two vehicles come with two variants of the turret. As both carry the 76mm gun these simply offer you variations on a theme. The crew figures are all from AB.
The closest I have come to seeing one of these is this 122mm howitzer at the Cambodian War Museum, it's the same gun that was mounted in the the adapted T-34 chassis to make the SU-122.