As far as I am aware, the following countries have no unmapped places, as of 9 April 2018:
Comment from Viajero Perdido on 14 April 2018 at 15:39
I see Hong Kong misses because of three remote villages. That’s “villages” in the local lingo, but almost certainly hamlets in the OSM world. (Wiki says village is 1000+ people.)
BTW, my own region (Alberta, Canada) is vast farmland with scattered hamlets, almost uniformly labelled Village by an old import. Or Town when Village is more appropriate, etc. I’m not sure what to do, if anything, about that. It might be a global problem, and that’s bigger than I’m willing to take on.