This is a mod concept that tries to adapt the downsides of the final boss blinds into decks. These are probably going to be very unbalanced but it'll still be fun. I can't figure out how to get steammodded to work so the best I can do is try to make art for each deck. Here are my ideas
Dead Plant Deck (verdant leaf): Spectral packs appear 2x more often, spectral cards can appear in the shop, spectral cards can no longer destroy jokers, all cards are debuffed each blind until a joker is sold, can not encounter the verdant leaf blind
Musical Deck (cerulean bell): Forces 1 card to always be selected, applies a random enhancement to and retriggers forcibly selected card 5 times if in play, can not encounter cerulean bell boss blind
Divine Deck (Violet Vessel): gives a negative copy of a random joker after each defeated boss blind, hands level up twice as fast, start with telescope, crystal ball, and omen globe, blinds scale 5x as fast, can not encounter violet vessel boss blind
Squirrel Fur Deck (Amber Acorn): start with a negative bull, bootstraps, and temporary to the moon joker, all jokers are shuffled and set face down after each hand played, can not encounter amber acorn boss blind
Glitter Heart Deck: disables a random joker each hand, jokers without seals are given a random (perminant) seal at the start of the round, jokers with seals cost and sell for as much as they would without one, can not encounter crimson heart boss blind