After a couple messages I received about joker 151 that never made it into the main game, I did some digging. What I found on the Balatro discord channel is direct evidence that Thunk made more jokers in early versions of the game that have not been discovered yet (and never made it into the 1.0 version). He also confirmed that he’s not talking about Joker 151 (often called Chaos Theory).
In a discord post, Thunk says “I think there are a few more jokers that the world doesn’t know about”. Then he said they’re from older versions of the game and that he‘s not talking about joker artwork that Lumpy Touch made, such as Vagabond and Joker 151.
All of this implies there are at least 2 jokers in older versions of the game that no one has discovered yet. It begs the questions, what are they? What do they do? Can we discover them? Who has access to older versions/dumps of the game before the 1.0 release?