Sort:  

Uganda starts with a U. Soviet Union starts with an S. 😁
United States too. Hungary in German: Ungarn.
If I can't think of any more, there probably are not many more. I must have forgotten some countries...

Yeah, I mean they should have remembered the name of their own country at the very least xD

Of course...
Uganda - Ukraine - United Arab Emirates - United Kingdom - United States - Uruguay - Uzbekistan