Patron saints are a bit weird. Apart from Ireland, Scotland, Wales and England could you name any other countries'? They probably have them but I don't know what they are. In fact the whole idea of saints is a bit weird.
Does the USA have a patron saint? Australia?
England, Bosnia and Herzegovina, Georgia, Ukraine, Malta, Ethiopia, as well as Catalonia and Aragon in Spain, and Moscow in Russia, have claimed George as their patron saint. That's just one Saint. Are you betting the rest of Europe doesn't have a patron Saint.
BTW there's other areas of countries who venerate St George such as a region in Bavaria that apparently has a ride out as part of their celebrations.
BTW the top paragraph came from Wikipedia but I did see another site that had about 15 countries or regions of countries that had St George as a patron saint. Not surprising really considering nationalism and religion go together hand in hand with symbolism like patron saints.