She can end games on the spot if you have much of a board with the Infest / Overrun combo
When the battlefield gets too full for someone's liking, or they need a clear board to make their next move a player may use an instant, sorcery, artifact, or even creature to wipe the board and remove creatures, artifacts, or enchantments from play
No Magic cards should be over $X, or else we wouldn't need fake cards
: Put a +1/+1 counter on up to one target creature
In the case of Yuna, Grand Summoner, this card is available at an upcoming event at WPN stores while supplies last
Spend this mana on Nexus of Fate, one of the silliest extra turn spells ever printed, which lets you chain together extra turns until your Reclamations give you enough mana for a lethal Expansion / Explosion