I picked up some 15mm Russian Buildings from Minibits. They are very cheap, but turn out pretty good. I did the minimum with them and I like how they ended up. They can be used for pretty much any period (and theatre, really). There's a few more pictures on my blog (including some other stuff), have a look here:
https://www.stormofsteelwargaming.com/2019/05/russian-farms.html