Like kicker and cycling, its a deciduous mechanic: Magic designers use it when needed , and its not necessarily in every set, or a set's main mechanic
Later in the game, when you have more mana, you can activate Maeve, Insidious Singers ability multiple times, giving you good control over every players board and also drawing you a lot of cards
Best Saga Payoffs There are a good number of cards that give you an additional benefit when a saga reaches its final chapter
Promo-A series Promo-B series In the game, while some of these cards are obtainable at any time, others, like those added with a limited-time drop event, can only be added to your collections during the associated event window
Tolkien (might not have) intended
This is not science fiction