Leif, Patient Sage

You may look at the top card of your library at
any time.
Whenever a nonland permanent an opponent controls becomes tapped, if it isn't being declared
as an attacker, put a stratagem counter on Leif, Patient Sage
Remove X stratagem counters: reveal the top card
of your library. If the revealed card has mana
value X, you may cast it without paying it's mana
cost.
Partner with Izzy, Violet Sorceress