In development, the team tried out a vanishing mechanic where a summon-like creature would slowly die over several turns, which was read as a downside
This works out quite well, as Elminster's +2 allows you top draw a card and scry two, reliably allowing access to this cost reduction
Then, all your other characters can mercilessly attack your opponents characters
They are fundamental in shaping the way Magic looks today, but these cards arent it
With the right combinations in play, like Serperior, Celebi can amass massive amounts of energy, allowing Celebi to constantly flip coins and easily pass 100-150 points of damage
Sandsteppe Outcast, Eldrazi Skyspawner, and Dauntless Cathar are fantastic cards, and Nearheath Chaplain was a bomb uncommon