Gaia, Mother Nature

Indestructible
During your own turn, you may tap forests your opponents controll to add mana to your manapool.
{2}{g}{t}: untap all forests. Until end of turn all
forests on the battlefield become 3/3 green
elemental creatures. Put three +1/+1 on all
forests you controll.
Partner with Tartaros, the endless Abyss