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i like red's avatar because he's powerful and mysterious, in the mysterious and "power revealed" forms
as for the couple, it symbolizes love, which im with :) also the obvious reason a person would have this as their avatar
i think you get global driver or win them through an event, like this oras article the sun&moon is hosting right now, or the ugt (or something, i forgot, but the games room hosted a common game event which that was the 1st place prize) Very_shiny_genesect
These three favorites sprites is my favorite because of a mysterious thuggish demeanour, except the fourth one the fourth sprite symbolizes love, and being a bachelor at best.