one piece booster box prices Collection: Includes Six Leaders with New Effects One Piece Card Game -

Delirium At the beginning of your end step, if there are four or more card types among cards in your graveyard, transform Autumnal Gloom

This card was probably designed to work with spacecrafts like The Seriema

By fast mana, I mean methods to get ahead of the curve early in the game, most likely on turn 1

Repeatable token effects are the best, and for that we have: Titania, Natures ForceTitania, Natures Force Rendmaw, Creaking NestRendmaw, Creaking Nest Grist, the Hunger TideGrist, the Hunger Tide Giant AdephageGiant Adephage Formless GenesisFormless Genesis Demonic CovenantDemonic Covenant Crawling SensationCrawling Sensation One-time effects are good too, like: Hornet QueenHornet Queen Ishkanah, GrafwidowIshkanah, Grafwidow ArachnogenesisArachnogenesis And lets not forget our other important theme, which is card types

Buying cards like this is more of a risk

Should your entire deck only contain one creature type, Cavern of Souls can effectively generate any color of mana