I’m not really a yaoi fan, but if I was one, the only Hetalia pairing that I ship would definitely be AmeChu(AmericaxChina). Why?
Look at the real life situation that’s happening. The economics they share(and America having a big ass debt), how they influence each other culturally, and even their personalities of how they’re very similar but at the same time are very different towards each other(think of how comedic situations the two dorks would be in).

However, like I said, not a yaoi fan, which is why the Herero version of AmeChu(both sides) is just as adorable as the yaoi version, and I ship them hard. ^w^