Yggdrasil, The World's Roots

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
Dryad, Fungus, Plant, Saproling, and Treefolk creatures you control get +0/+1 for each forest
you control and have "{t}: add {g} to your mana
pool".
{4}{g}{g}{g}: Dryad, Fungus, Plant, Saproling, and Treefolk creatures you control get +1/+0 until
end of turn for each forest you control.