A very interesting topic indeed. I think you will find that ALL Slavs are very proficient at swearing. I am from Croatia and my favourite one is a mixup of a couple of different ones into a single one: Jebo ti Isus krvavi raspeti i Marija mater. (Bloody and crucified Jesus and Mary fucked your mother)
*note, I don’t think this is a commonly used one since it kinda came to exist when I hit my toe and it just kinda came out.

All I can say that in Croatia, out favourite topics are dogs, mothers, God, Jesus, penis and vagina in all kinds of variations and combinations.