The voltron charakters as a card game:

Shiro: i feel he's the king of diamond

Allura: queen of heart (obviously)

Lotor: joker of spades

Lance: Joker of hearts

Pidge: Ace of spades or clubs

Keith: Ace of diamond or spades

Hunk: Ace of hearts

Narti: joker of diamonds

Acxa: queen of spades

Zethrid: queen of clubs

Ezor: joker of clubs

Haggar: queen of diamonds

Zarkon: king of spades

I just guessed those. All sorting is debatable. You may as well make your own headcanons ^^

Bonus:

Black lion: Ace of spades

Red lion: Joker of Spades

Blue lion: queen of hearts

Green lion: Joker of Clubs

Yellow lion: king of diamonds