Theres no way of quantatively ranking which cards with side effects are the most powerful, as they all have unique benefits when played against opponents
This diagram of a typical Lorcana card helps to show what each part of the card means: Character cards have Strength , Willpower , and Lore values
Darkness of Eternity Dark Ritual could do some pretty obscene things, but itll also feel pointless if you flood out or the game goes long
It can be intimidating at first if you look at all of the markings on a single card, but once you break through that, the rules for Disney Lorcana are surprisingly straightforwardand fit on a single sheet of paper
Rather than using the Transform mechanic, it could just have a buffing effect that applies to itself throughout the fight, possibly being powered by killing Legendary Creatures
There are all types of cool effects with helpful or clever uses