The most popular one is of course Пиндосы (Pindosy, plural). The origin is vague and believed by some to go down to the times of the Russian empire when somewhere in the Balkans there allegedly lived some nasty Greeks in the mountain range by the name of Pindos. No one had any interest in that until the Yugoslavian crises broke out where American and Russian peace keeping contingents got to be neighbors in Bosnia. I guess there was no love lost between the two and our guys dug out the term from the pits of history. It's only my guess, but I'm pretty sure it's correct, that the moniker grew on our men because it was in tune with our very popular derogatory term Пидорас, which means Gay, Pederast or, mildly put, a deplorable in every imaginable aspect individual.