On higher stakes, an Eternal Holo Madness shows up in the shop during Ante 2. The next few shops will contain Spectral packs that have Ankh in them, allowing several copies of Madness without destroying each other.

For those curious, here's the rundown and how I personally played this seed:

play checkered deck normally, playing flushes.

ante 1, shop 2 (after Big Blind) - get riff-raff for jokers to sell.

ante 1, boss (the hook) - only play spade flushes.

ante 2, shop 1 (after the Hook) - grab Overstock

ante 2, small blind - riff-raff gives you Sly Joker. without spending any discards, play a spade flush and then a hearts flush (both contain pairs)

ante 2, shop 2 (after Small Blind) - Holo Eternal Joker appears. sell all jokers and buy it

ante 2, shop 3 (after Big Blind) - a mega spectral pack is in the shop. it contains an Ankh

while probably not necessary, i recommend grabbing Telescope from the shop after defeating the ante 2 boss to level up flushes.

ante 4, shop 3 (after Big Blind) - a spectral pack is in the shop. another Ankh is inside

from this point on, it should be smooth sailing to endless. if i recall correctly, a third Ankh in a spectral pack will be available somewhere around ante 10. i only made it up to ante 13 with this seed, but i'm sure with some shenanigans it could go pretty far :)