As I mentioned in another post, Ive managed to acquire a few packs of Disney Lorcana cards at various D23 events in the last year
For example, if an effect allowed you to search your library for a land card, you could find Jidoor, but if you were searching for a sorcery card, you couldn't find Overture
It involves copying your creatures and using energy counters to let them stick around (or, in some cases, letting them die to take advantage of death triggers)
All of a sudden, all your songs with cost three ink or less have the potential to double their effect
The spell will be put into its owner's graveyard and you won't get to cast it again on your next turn
This is often used as a way to keep old cards up to date with current terminology, but can also be sparingly used for the sake of balancing the game