Twisted Fate's Card Suites
After typing up my idea for what a reworked Twisted Fate could be (here: https://boards.na.leagueoflegends.com/en/c/skin-champion-concepts/k5A88nKG-twisted-fate-rework-concept ) and putting some more thought into how his cards could look more like real playing cards, I realized he actually already has 4 card suites.
You might be wondering, "four? Gold, Blue, and Red makes three." But when he uses his ultimate, he shows the fourth card suite, which is green. (you have to look at the target location, not your current location)
The thing is, though, there's no lore about what the suites actually are, or even what they're technically named. So here are my thoughts on what they could be.
Blue - Oracles
Doesn't really need to be specific. It can be as ambiguous as the "oracle" referenced by various vision items. 
For the purpose of my rework suggestion, the Queen of Oracles card would be a seer. (I figure we're at the point where more detailed cards would be okay.)
Red - Warriors Could be an indirect reference to Aatrox, spawning from old legends of soldiers who found his sword and were transformed. Which is why the suite is a red sword. What that'd look like for the Jack is pretty obvious.
Gold - Bound Could be a more direct reference, this one being to the golden chains used by Demacia's prisons. The Bound King card would, of course, be a man wrapped in said chains.
Green - Gatekeepers Could be a reference to two particular mages with the extremely rare ability to teleport: Ryze (who's already the subject of legends thanks to his age), and Ne'Zuk (for those who don't know, that's the original Shuriman owner of Ezreal's gauntlet, "who was said to be able to jump instantly from one place to another"). Even the color is a mixture of Ryze's blue and Ne'Zuk's Shuriman gold.
And they could be manufactured by Zhonya, hence the hourglass on the back.
So rather than the cards being unique to Twisted Fate, he as the Card Master has the ability to use the magic represented by the suites.
