If you'd like feedback I have some, otherwise just ignore this. I did a little testing for these.
So above you have the Microtransaction Joker listed as gaining X0.01 Mult per item purchased but you have it coded to gain X0.1 Mult. Not sure which is intended but one is quite weak and the other STRONG. I would play with the XMult gain a little. You might have to really spend a bit of time playing with this one to get that number right, but you'll get it.
Both Microtransaction and Buzzer Beater need something like this to prevent the XMult message from appearing when they are both only at X1 Mult " if context.joker_main and card.ability.extra.Xmult > 1 then
return {yada yada blah " They also should both have Perishable set to false.
Buzzer Beater is missing a ". . .and not context.blueprint. . ." bc it will upgrade twice if you're using Blueprint. Blueprint is only supposed to return the XMult again, not upgrade it again. Unless you want it to be unique like that.
Judge Jury and Executioner has 3 separate 1 in 4 checks go off and I didn't expect that based on the Joker's description. You might find that you want it to work differently in the future.
In the Jokers Spritesheet image you need to leave one empty pixel border around each card. Your cards are too close together
Hope this helps