We all know that there are missing nations that have to be in Hetalia..

Mexico

Philippines

Croatia

Brazil

Argentina

Indonesia

Malaysia

Ireland

Scotland?(is he canon or what? Well yeah, he did appear in the show just once but didn't seem to have in common with the real Scotland that has a red hair and wearing a blue uniform with white stuffs that represents his flag)

Greenland

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If you are looking for other nations that is not on the list, you can comment it :)))