Imbued Deck

You can imbue your cards with various reactants, causing pseudo-magical effects. You can spend 8 hours imbuing an entire deck with one ability. You may spend 1 Gambit Die to activate one of the following effects, though only 1 effect at a time. At 11th level, you may add a second effect to your cards.

Many of these effects and future abilities require creatures to make a saving throw. Your save DC is 8 + proficiency bonus + a Gambit die

Charcoal Do I feel a hot streak coming up, or is it just my cards? When you hit a creature, you light it on fire for 20 seconds (or about 3 combat rounds). It takes 1d4 fire damage every round of combat. Hitting a flammable object that is neither being held nor worn causes it to combust. Damage increases to 1d6 at 5th level, 1d8 at 11th level, 1d10 at 17th level. Any cards used this way cannot be recovered after combat.
Venom Not poison! Well, it's poison, but the mode of delivery is what makes it venomous! Hit targets must succeed a Constitution saving throw or receive the Poisoned condition. Starting at 11th level, the creature takes half of the rolled Gambit Dice in poison damage (round down) at the start of their turn, continuing until they recover at least 1 hit point. Any cards collected after battle are no longer imbued.
Flash Paper Suddenly, gone. When you hit a target with this attack, they must succeed a Wisdom saving throw or received the Stunned condition until the start of your next turn. Any cards used this way cannot be recovered after combat.
Razorblades Certainly gluing small razors to your cards counts as imbuing them, yes? Roll a Gambit die and add it to the damage of your cards. Your target also takes the rolled Gambit Die in bleeding damage at the start of their turn for 20 seconds (or about 3 rounds) or until they recover at least 1 hit point, due to blood loss.
Hissing Cards Honestly, it's amazing the cards are even staying together. Starting at the 9th level, you may imbue your cards with acid! Add one Gambit Die of Acid Damage to your attack. Hit targets must succeed a Constitution Saving Throw of 5 plus your Proficiency Bonus or remove any armor they are wearing. Add another Gambit Die to damage at 17th level. Any cards used this way cannot be recovered after combat.