The variety of every Yu-Gi-Oh protagonist's traveling/spirit companions has always been interesting. We went from spirit of dead pharaoh to dead teacher+vengeful spirit, mythic dragon, dimensional counterpart, arrogant AI, an arrogant drone, and a spaceship controlled by 8.8 million aliens. Love it.
Which anime main girl's decks fit their character/personality, & development the best? You can rank them, although if you ask what personality, I wouldn't go that far, but the guys usually get these discussions, so let's focus on the ladies. (Yes I forgot to get an image of Aoi with her Marincesses)
Daina was a pretty solid character looking back. First willing to do anything for his brother, to cheating going neck and neck with teammates of the Four Spin Emperor, becoming a team leader and making it to the semi-finals of the World League, almost beating #3 in the world, Daina's pretty awesome.