Canopy Baloth

Landfall — Whenever a land you control enters, Canopy Baloth gets +2/+2 until end of turn.

Yavimaya Dryad

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
When Yavimaya Dryad enters, you may search your library for a Forest card, put it onto the battlefield tapped under target player's control, then shuffle.

Generated Horizons

At the beginning of your upkeep, create a Forest land token.

Arboreal Grazer

Reach
When Arboreal Grazer enters, you may put a land card from your hand onto the battlefield tapped.

Horizon Seeker

Boast — {1}{G}: Search your library for a basic land card, reveal it, put it into your hand, then shuffle. (Activate only if this creature attacked this turn and only once each turn.)

Undergrowth Champion

If damage would be dealt to Undergrowth Champion while it has a +1/+1 counter on it, prevent that damage and remove a +1/+1 counter from Undergrowth Champion.
Landfall — Whenever a land you control enters, put a +1/+1 counter on Undergrowth Champion.

Forest

Lair of the Hydra

If you control two or more other lands, Lair of the Hydra enters tapped.
{T}: Add {G}.
{X}{G}: Until end of turn, Lair of the Hydra becomes an X/X green Hydra creature. It's still a land. X can't be 0.

Broken Bond

Destroy target artifact or enchantment. You may put a land card from your hand onto the battlefield.

Thriving Grove

Thriving Grove enters tapped. As it enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Kazandu Nectarpot

Landfall — Whenever a land you control enters, you gain 1 life.

Jaddi Offshoot

Defender
Landfall — Whenever a land you control enters, you gain 1 life.

Fertile Footsteps

Search your library for a basic land card, put it onto the battlefield, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Beanstalk Giant

Beanstalk Giant's power and toughness are each equal to the number of lands you control.

Beanstalk Giant // Fertile Footsteps

Enter the Unknown

Target creature you control explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)
You may play an additional land this turn.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.