judging by the replies it is perfectly obvious so hurray
Alternative idea: why not just make ace versions of everything by sticking a big black Spade symbol in the middle of whatever flag you want
heck let's make the Ace flag a black spade on like three grey stripes
DID YOU KNOW: The suit of Spades in common playing card decks comes from the tarot suit of Swords.
The suit of Swords is generally associated with the element of fire, which is the element associated with actions and will. However, some interpretations swap with Wands and link Swords with Air instead, which is the element associated with intellect.
I don't actually know all that much about like, tarot and astrology and alchemy, I just am a big giant nerd for elemental associations. That's why I want to make my own elementally themed card deck... >.>