Improvisation Capstone

Exile cards from the top of your library until
you exile cards with total mana value 4
or greater. You may cast any number of spells
from among them without paying their mana costs.

Paradigm (Then exile this spell. After you first
resolve a spell with this name, you may cast a copy
of it from exile without paying its mana cost at the
beginning of each of your first main phases.)