I mean, what in particular? Take the UK, Germany, France, Spain - in none of those major European nations does the predominant party claim to be the sole representative of their dominant ethnicity's interests qua ethnic interests. They typically compete on non-ethnic grounds. The Republican Party is almost unique in terms of its size, success, and focus on being the sole political representative of the 'true' American people. Le Pen didn't win.
I dunno what ethnostate means but I was assuming it meant "a nation-state formed around the concept of a single ethnicity" which appears to me to be almost every country in Europe. The stuff that determines why Alsace-Lorraine belongs to France (because "french people live there"). Here's my tabulation:
Andorra: 33% Catalan
Australia: 91.2% White
Austria: 92% Austrian/German
Belgium: 55% Flemish, 35.6% Walloon (who live in the north and south respectively)
Canada: 21.6% Canadian, 14.1% English, 10.6% French, 10.1% Scottish, 9.3% Irish, 6.8% German, 3.1% Italian (75.6% White)
Chile: 88% White Hispanic
Denmark: 89% Danish
Finland: 89% Finnish
France: 89% French origin, but ethnic makeup impossible to determine by law
Germany: 91% German
Greece: 93% Greek
Hungary: 83% Hungarian
Iceland: 93% Icelandic
Italy: 92% Italian
Japan: 98.5% Japanese
Malta: Almost entirely Maltese
Ireland: Irish: 84.5%
Netherlands: 81% Dutch
New Zealand: 74% White
Norway: 94.4% Norwegian
Portugal: Almost entirely "Mediterranean"
Monaco: 47% French
Sweden: Almost entirely "Swedish"
Switzerland: 65% German, 18% French
Taiwan: 95% Han Chinese
United Kingdom: This one's difficult for me. You're going to have to break it down because I'm having trouble with it.
United States: 63% Non Hispanic White
Spain: Not even going to attempt this.
(In New World countries, white is more important than specific European ethnicities, whereas in Europe I used ethnicity a little more precisely.)
If you're defining ethnostate as a country transitioning to or is already a Herrenvolk democracy, then I'd say that those only appear in countries that are at risk of losing ethnostate status. As far as the developed world is concern, only countries like the United States, Canada the UK, and Spain (just barely) have really managed to have a multiethnic experiment in democracy and survived. That's notable.