Age Of Arcanum

Finite 5 (This card enters the battlefield with five
time counters. At the beginning of your upkeep or if
this card would be removed from the battlefield,
remove a counter from it. When there are no time
counters left on it, exile it.)
Players may play instants and sorceries without
paying their mana costs.
Though this is the end of the age of heroes, it has
saved its best for last.