Ulvenwald Hydra

Reach
Ulvenwald Hydra's power and toughness are each equal to the number of lands you control.
When Ulvenwald Hydra enters, you may search your library for a land card, put it onto the battlefield tapped, then shuffle.

Rubblehulk

Rubblehulk's power and toughness are each equal to the number of lands you control.
Bloodrush — {1}{R}{G}, Discard Rubblehulk: Target attacking creature gets +X/+X until end of turn, where X is the number of lands you control.

Ashaya, Soul of the Wild

Ashaya, Soul of the Wild's power and toughness are each equal to the number of lands you control.
Nontoken creatures you control are Forest lands in addition to their other types. (They're still affected by summoning sickness.)

Wilderness Elemental

Trample
Wilderness Elemental's power is equal to the number of nonbasic lands your opponents control.

Crash of Rhino Beetles

Trample
Crash of Rhino Beetles gets +10/+10 as long as you control ten or more lands.

Maraxus of Keld

Maraxus of Keld's power and toughness are each equal to the number of untapped artifacts, creatures, and lands you control.

Multani, Yavimaya's Avatar

Reach, trample
Multani, Yavimaya's Avatar gets +1/+1 for each land you control and each land card in your graveyard.
{1}{G}, Return two lands you control to their owner's hand: Return Multani from your graveyard to your hand.

Dokai, Weaver of Life

{4}{G}{G}, {T}: Create an X/X green Elemental creature token, where X is the number of lands you control.

Budoka Gardener

{T}: You may put a land card from your hand onto the battlefield. If you control ten or more lands, flip Budoka Gardener.

Budoka Gardener // Dokai, Weaver of Life

Zendikar Incarnate

Zendikar Incarnate's power is equal to the number of lands you control.

Radha, Heart of Keld

During your turn, Radha, Heart of Keld has first strike.
You may look at the top card of your library any time, and you may play lands from the top of your library.
{4}{R}{G}: Radha gets +X/+X until end of turn, where X is the number of lands you control.

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

Waking the Trolls

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target land.
II — Put target land card from a graveyard onto the battlefield under your control.
III — Choose target opponent. If they control fewer lands than you, create a number of 4/4 green Troll Warrior creature tokens with trample equal to the difference.

Ziatora, the Incinerator

Flying
At the beginning of your end step, you may sacrifice another creature. When you do, Ziatora, the Incinerator deals damage equal to that creature's power to any target and you create three Treasure tokens.

Branch of Boseiju

Reach
Branch of Boseiju gets +1/+1 for each land you control.

Boseiju Reaches Skyward

(As this Saga enters and after your draw step, add a lore counter.)
I — Search your library for up to two basic Forest cards, reveal them, put them into your hand, then shuffle.
II — Put up to one target land card from your graveyard on top of your library.
III — Exile this Saga, then return it to the battlefield transformed under your control.