Centaur Rootcaster

Whenever Centaur Rootcaster deals combat damage to a player, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Forest

Beastmaster Ascension

Whenever a creature you control attacks, you may put a quest counter on Beastmaster Ascension.
As long as Beastmaster Ascension has seven or more quest counters on it, creatures you control get +5/+5.

Courser of Kruphix

Play with the top card of your library revealed.
You may play lands from the top of your library.
Landfall — Whenever a land you control enters, you gain 1 life.

Stonehoof Chieftain

Trample, indestructible
Whenever another creature you control attacks, it gains trample and indestructible until end of turn.

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When Rancor is put into a graveyard from the battlefield, return Rancor to its owner's hand.

Pharika's Disciple

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)

Pheres-Band Warchief

Vigilance, trample
Other Centaur creatures you control get +1/+1 and have vigilance and trample.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Dowsing Shaman

{2}{G}, {T}: Return target enchantment card from your graveyard to your hand.

Nissa's Pilgrimage

Search your library for up to two basic Forest cards, reveal those cards, and put one onto the battlefield tapped and the rest into your hand. Then shuffle.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, search your library for up to three basic Forest cards instead of two.

Mountain

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Rhonas's Monument

Green creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, target creature you control gets +2/+2 and gains trample until end of turn.

Stonebrow, Krosan Hero

Trample
Whenever a creature you control with trample attacks, it gets +2/+2 until end of turn.

Rampant Growth

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

Centaur Omenreader

As long as Centaur Omenreader is tapped, creature spells you cast cost {2} less to cast.