I'm thinking things like flagpoles in the yard.
Like you waste however much money and resources to keep your non-native grass around and they drop in a 60 foot pole into it to be able to fly an American flag and flag for whatever shitty college you went to.
What other things are there?
I think you ought to narrow that "Europe" bit down. In Berlin before 2006 it was really rare to see a flag and was "Ew", nowadays it still is "Ew" but a bit more common, though it still is really rare to see it at single homes (and then not as prominently as in the US).
Though we got a lot of :rainbow-has: flags around the city, that is nice.
I'd prefer not to for safety reasons. I live in a immigrant community in a big city were it's very much not a thing but as I stated in my first post, in rural communities and suburbs were people live in houses with lawns it is a thing.
Also, Berlin has a huge leftist and alternative community compared to many other European capitals and patriotism seems to be quite frowned upon by many Germans for obvious reasons, not really representative of Europe as a whole in my opinion.