Arbor Elf

Burgeoning

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Zendikar Resurgent

Whenever you tap a land for mana, add one mana of any type that land produced. (The types of mana are white, blue, black, red, green, and colorless.)
Whenever you cast a creature spell, draw a card.

Exploration

You may play an additional land on each of your turns.

Wild Growth

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

Omnath, Locus of Mana

You don't lose unspent green mana as steps and phases end.
Omnath, Locus of Mana gets +1/+1 for each unspent green mana you have.

Fyndhorn Elves

Llanowar Elves

Birds of Paradise

Vernal Bloom

Whenever a Forest is tapped for mana, its controller adds an additional {G}.

Utopia Sprawl

Enchant Forest
As Utopia Sprawl enters the battlefield, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.