Thunderscape Familiar

First strike
Black spells and green spells you cast cost {1} less to cast.

Herd Baloth

Whenever one or more +1/+1 counters are put on Herd Baloth, you may create a 4/4 green Beast creature token.

Krosan Warchief

Beast spells you cast cost {1} less to cast.
{1}{G}: Regenerate target Beast.

Slinza, the Spiked Stampede

Beast spells you cast cost {2} less to cast.
Each other Beast creature you control enters with an additional +1/+1 counter on it.
Whenever Slinza or another creature with power 4 or greater enters, you may pay {1}{R/G}. When you do, Slinza fights target creature you don't control.

Sylvan Library

At the beginning of your draw step, you may draw two additional cards. If you do, choose two cards in your hand drawn this turn. For each of those cards, pay 4 life or put the card on top of your library.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Anara, Wolvid Familiar

During your turn, commanders you control have indestructible. (Effects that say "destroy" don't destroy them. A creature with indestructible can't be destroyed by damage.)
Partner (You can have two commanders if both have partner.)

Rampaging Baloths

Trample
Landfall — Whenever a land you control enters, you may create a 4/4 green Beast creature token.

Woodland Liege

Whenever a Beast you control enters, draw a card.

Shaleskin Bruiser

Trample
Whenever Shaleskin Bruiser attacks, it gets +3/+0 until end of turn for each other attacking Beast.

Siege Behemoth

Hexproof
As long as Siege Behemoth is attacking, for each creature you control, you may have that creature assign its combat damage as though it weren't blocked.

Blossoming Bogbeast

Whenever Blossoming Bogbeast attacks, you gain 2 life. Then creatures you control gain trample and get +X/+X until end of turn, where X is the amount of life you gained this turn.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Aether Charge

Whenever a Beast you control enters, you may have it deal 4 damage to target opponent or planeswalker.

Fangren Marauder

Whenever an artifact is put into a graveyard from the battlefield, you may gain 5 life.

Rampant Growth

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

Urza's Incubator

As Urza's Incubator enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Krosan Drover

Creature spells you cast with mana value 6 or greater cost {2} less to cast.

Ezuri's Predation

For each creature your opponents control, create a 4/4 green Phyrexian Beast creature token. Each of those tokens fights a different one of those creatures.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Craterhoof Behemoth

Haste
When Craterhoof Behemoth enters, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

Vitality Charm

Choose one —
• Create a 1/1 green Insect creature token.
• Target creature gets +1/+1 and gains trample until end of turn.
• Regenerate target Beast.

Emerald Medallion

Green spells you cast cost {1} less to cast.

Totem Speaker

Whenever a Beast enters, you may gain 3 life.

Feral Throwback

Amplify 2 (As this creature enters, put two +1/+1 counters on it for each Beast card you reveal in your hand.)
Provoke (Whenever this creature attacks, you may have target creature defending player controls untap and block it if able.)

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Contested Cliffs

{T}: Add {C}.
{R}{G}, {T}: Target Beast creature you control fights target creature an opponent controls. (Each deals damage equal to its power to the other.)

Cryptic Gateway

Tap two untapped creatures you control: You may put a creature card from your hand that shares a creature type with each creature tapped this way onto the battlefield.

Thunder of Hooves

Thunder of Hooves deals X damage to each creature without flying and each player, where X is the number of Beasts on the battlefield.

Berserk Murlodont

Whenever a Beast becomes blocked, it gets +1/+1 until end of turn for each creature blocking it.

Wirewood Savage

Whenever a Beast enters, you may draw a card.

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Boxing Ring

Whenever a creature you control enters, it fights up to one target creature you don't control with the same mana value.
{T}: Create a Treasure token. Activate only if you control a creature that fought this turn.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Ravenous Baloth

Shadow in the Warp

The first creature spell you cast each turn costs {2} less to cast.
Whenever an opponent casts their first noncreature spell each turn, Shadow in the Warp deals 2 damage to that player.

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.

Neyith of the Dire Hunt

Whenever one or more creatures you control fight or become blocked, draw a card.
At the beginning of combat on your turn, you may pay {2}{R/G}. If you do, double target creature's power until end of turn. That creature must be blocked this combat if able. ({R/G} can be paid with either {R} or {G}.)

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.