Yggdrasil,The World Tree

{t}: Add a mana of any color to your mana pool
{4}{t}: Add 7 mana of any color to your mana pool
{3}{t}: Add mana of any color to your mana pool
equal to the number of creatures you control
{2}{g}{w}{t}: Add mana of any combination that
target player could add to their mana pool to your
mana pool