Two things matter most: 1) Sleeves + shuffle feel (dont accidentally build a sticky cube) Use consistent sleeves across the entire cube
Storm, Force of Nature WotC couldnt resist giving the first Storm card the mechanic of the same name, right
Works as a win condition when paired with infinite mana, drawing our deck into our win condition(s)
Transforming Double-Faced Cards The other major theme of Final Fantasy thats represented in a mechanic is the epic boss battles seen throughout the series
Infinite Guideline Station Infinite Guideline Station is a tough one to pull off because outside of hybrid mana cards, multicolored permanents tend to be more expensive and legendary
The cards in the Unfortunate Events Deck can be introduced at random, given to players in secret at the table, and of course used to spark a brand new Call of Cthulhu story