Sharra, High Druid

Eminence - At the beginning of your upkeep, if Sharra, High Druid is in the command zone or on the battlefield, if you control three or more elves, non-elf creatures get -1/-1 until the end of your next turn.
Whenever a nontoken elf enters the battlefield, you may pay {w}{b}{g}, if you do, create a 1/1 green Elf creature token with:
"{t}: Add {g} to your mana pool.".