Pixel is a normal/rock type, because they're a pixel therefor a porygon in disguise but rock because of their avatar.
@Hraesvelgr is a Dragon/Steel type because I think his avatar is ..exactly that? a dragon (to be more exact, I believe it looks too much like the Flying Wyvern, Remobra!) with a basic metal shield infront.
Braviary is Normal/Water since they have a Normal Type Meowth and there's lots of blue in that postbit!
@SkittleBox is a fire and rock type because Hetalia is about countries and by extension, the earth, and America is about as passionate and fiery as they get
@Enasencca is Ice/Psychic because her avatar is Lake Valor's guardian and her current Pokémon buddy is Seel!
@BZRich64 is a Fight/Flying type because their current rank is 'Black belt' ...and Pidgeot is their current partner Pokémon.
@Fizzysoda looks like an Ice/Fairy type, because their signature says "Magical Girl" and their partner Pokémon is Alolan Vulpix!
@Wings is a Normal/Flying type because they seem pretty normal (in a good way I promise you) and those flap flappers scream flying type.