I just read this article from Afar that says CLEAR is in Europe at some airports (granted, not a lot). But it mentions you can avoid paying the CLEAR fees, and book your security slot for free to avoid security lines.
Again, there are not a lot of airports, but if you're flying from BER, AMS, FRA, HAJ and FCO, you can try this out. The article says its not always guaranteed, and sometimes it allows it and sometimes it doesn't. But if you are flying from Berlin, say, it would probably be worth a quick try at the website to see if it will work for you. And according to CLEAR, they are adding more airports. Keflavik has already finalized a pilot program.
I hope it works - I'd love to hear if it's successful for anyone traveling now. https://www.afar.com/magazine/at-these-europe-airports-you-can-skip-security-lines