Paper Dragon Achievement can be completed by smashing 150 Pinatas. Pinatas can be found in all capital cities (10 pinatas per city), but most of them are in Lion’s Arch. Don’t forget that you can always change overflow servers.
Rata Sum Paper Dragon Pinata locations
The Grove Dragon Pinata locations
Divinity’s Reach Dragon Pinata locations
Wooded Kingdom Moons in Super Mario Odyssey