Keyleth

Keyleth's toughness is equal to the number of
forests you control.
{g/u}{r/g}{u/r}: Exile Keyleth; Put either a 4/4
Elemental Creature token with flying, a 6/1
Elemental creature token with First Strike, or
a 5/5 Elemental creature token with Trample
onto the battlefield with, "When this creature
dies return Keyleth from exile to the battlefield".