Card collecting to help you, so you don't have to make the same mistakes I did, when I started
If you pay the full seven mana for her, Nissa is very mighty, capable of making 8/8 tokens, destroying umpteen artifacts and enchantments throughout the course of a game, and even pumping up your whole board with her ultimate right away
A commander that is just incredibly powerful would not qualify for the Game Changers list
He was literally the biggest, scariest creature in the game in 1993, and with both Animate Dead and Dark Ritual in the first set, he could hit the battlefield well before turn seven, so he was a very in-demand card
But it is far gentler
for example, F will rotate out once the I regulation mark cards are released