I think it would be cool to see the card game "Regicide" be referenced as a joker in the game or maybe also get a jimbo's friends set of face cards too. Since its a game played with a regular deck of cards, it fits balatro pretty well because of that, and the game also has a focus on using joker cards too. (not like balatro joker cards, literal playing card jokers)
TLDR DESCRIPTION OF MY JOKER IDEA:
Goblin Joker (Common) - Transfers (Enhancement, Seal, Edition) to both selected cards at the round's first discard or hand played.
The jokers in the game look like the attached image, so if there is a joker made based off of the game then it should look like this. I dont have many ideas for what this joker could do, but I'd call it Goblin. Anyways, it could have a duplicating ability where it could transfer a card modifier to one different card using the first hand or discard of a round. The type of modifiers that it would duplicate over would change after every shop. For example, it would be on Enhancements, you go to the next shop and it changes to Seals.
So for example, its the start of a round and Goblin Joker is currently on Seals, and you want to transfer a purple seal to another card in order to get 2 purple seals discarded for the round to get more tarot cards.
Goblin Joker would act like the 'Death' tarot card joker like how Trading Card is like Hanged man and DNA is like Cryptid.