My recommendation is to play the Lobotomy Mod by itself or just with a few quality of life mods. It uses a lot of Lobotomy Corporation’s ideas and assets to create a completely unique psychological horror deckbuilding roguelite in slay the spire. This mod is based on a Japanese cult favourite monster management game, Lobotomy Corporation. Lobotomy is a unique mod where it starts off really simple, just adding some new wacky cards and a few new enemies to fight, but turns into something absolutely insane as you progress through and learn about the mechanics. Character mods that add new ways to play, Act mods that add new enemies to fight, relic mods, re balance mods, and so much more.
Since the release of the modding tools, there have been a lot of different kind of mods created for Slay the Spire.