While it's true that most countries have their homegrown version by now, I've used Craigslist myself in other countries, and it does have enough of a presence that it's actually maintained in over 50 countries which is no small feat.

Well, they are present in Denmark. I only managed to find a single item - an expensive apartment.

In Denmark the place to go is dba.dk or facebook marketplace.

Checking the portugese version - its 3 items in Lisbon.

I just checked the Croatian version and it has a total of 5 things listed for sale and 3 jobs.

Needless to say, there's a far more popular local alternative that basically every person in Croatia knows about (njuskalo.hr).

really even regionally. In Canada i've seen geo popularity across Kijiji, Craigs List, FB Marketplace, domain-specific communities with markets