Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Llanowar Elves

Doubling Cube

{3}, {T}: Double the amount of each type of unspent mana you have.

Forest

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Helix Pinnacle

Shroud (This enchantment can't be the target of spells or abilities.)
{X}: Put X tower counters on this enchantment.
At the beginning of your upkeep, if there are 100 or more tower counters on this enchantment, you win the game.