Interesting. I would love to see a number for Austria - until this month, it was IIRC one of the few EU countries which didn't require any form of identification for a prepaid phone.
It was the same for Romania but that is about to change because of a kidnapping/murder case and a media shitstorm regarding fake emergency number calls and geotracking of callers.
Finland still doesn't require identification for prepaid SIM cards.
Same with Lithuania. You can pick them up from supermarkets and news stands for a few euro.
UK as well. They are not as common as they used to be but they are still available.