When the canon's got a huge (and mostly male) cast of anthropomorphized countries, the fans inevitably will write lots of fanfics reimagining real-life historical events and international relations with these characters.
Okay, sometimes that's just an excuse to slash the cute nation-guys together, but there really are plenty of Hetalia fics full of thought, emotion, research, and/or even good romance. This page is proof of that.
These are recommendations made by Tropers for Hetalia: Axis Powers fanfics, all of which have to be signed to stay on the page. Feel free to add a fanfic of your own to the list, but remember to use the template found here.
You can also add to the current recommendations if you want. Refrain from posting Conversation in the Main Page though; that goes in the discussion page.