Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Talisman of Impulse

{T}: Add {C}.
{T}: Add {R} or {G}. Talisman of Impulse deals 1 damage to you.

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.

Game Trail

As Game Trail enters, you may reveal a Mountain or Forest card from your hand. If you don't, Game Trail enters tapped.
{T}: Add {R} or {G}.

Rugged Highlands

Rugged Highlands enters tapped.
When Rugged Highlands enters, you gain 1 life.
{T}: Add {R} or {G}.

Jaya's Immolating Inferno

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Jaya's Immolating Inferno deals X damage to each of up to three targets.

Genesis Hydra

When you cast this spell, reveal the top X cards of your library. You may put a nonland permanent card with mana value X or less from among them onto the battlefield. Then shuffle the rest into your library.
Genesis Hydra enters with X +1/+1 counters on it.

Timber Gorge

Timber Gorge enters tapped.
{T}: Add {R} or {G}.

Explosive Vegetation

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Mana Bloom

Mana Bloom enters with X charge counters on it.
Remove a charge counter from Mana Bloom: Add one mana of any color. Activate only once each turn.
At the beginning of your upkeep, if Mana Bloom has no charge counters on it, return it to its owner's hand.

Wildest Dreams

Return X target cards from your graveyard to your hand. Exile Wildest Dreams.

Animist's Awakening

Reveal the top X cards of your library. Put all land cards from among them onto the battlefield tapped and the rest on the bottom of your library in a random order.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, untap those lands.

Gruul Signet

Far Wanderings

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
Threshold — If seven or more cards are in your graveyard, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Xenagos, God of Revels

Indestructible
As long as your devotion to red and green is less than seven, Xenagos isn't a creature.
At the beginning of combat on your turn, another target creature you control gains haste and gets +X/+X until end of turn, where X is that creature's power.

Electrodominance

Electrodominance deals X damage to any target. You may cast a spell with mana value X or less from your hand without paying its mana cost.

Mountain

Strength of the Tajuru

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose target creature, then choose another target creature for each time this spell was kicked. Put X +1/+1 counters on each of them.

Gelatinous Genesis

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Llanowar Elves

Burn from Within

Burn from Within deals X damage to any target. If a creature is dealt damage this way, it loses indestructible until end of turn. If that creature would die this turn, exile it instead.

Hydra Broodmaster

{X}{X}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When Hydra Broodmaster becomes monstrous, create X X/X green Hydra creature tokens.

Fall of the Titans

Surge {X}{R} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Fall of the Titans deals X damage to each of up to two targets.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Gruul Guildgate

Gruul Guildgate enters tapped.
{T}: Add {R} or {G}.

Meltdown

Destroy each artifact with mana value X or less.

Rosheen Meanderer

{T}: Add {C}{C}{C}{C}. Spend this mana only on costs that contain {X}.

Farhaven Elf

When Farhaven Elf enters, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Journey of Discovery

Choose one —
• Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.
• You may play up to two additional lands this turn.
Entwine {2}{G} (Choose both if you pay the entwine cost.)

Goblin Offensive

Hooded Hydra

Hooded Hydra enters with X +1/+1 counters on it.
When Hooded Hydra dies, create a 1/1 green Snake creature token for each +1/+1 counter on it.
Morph {3}{G}{G}
As Hooded Hydra is turned face up, put five +1/+1 counters on it.

Sol Ring

Kodama's Reach

Guardian Project

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Dawntreader Elk

{G}, Sacrifice Dawntreader Elk: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Primordial Hydra

Primordial Hydra enters with X +1/+1 counters on it.
At the beginning of your upkeep, double the number of +1/+1 counters on Primordial Hydra.
Primordial Hydra has trample as long as it has ten or more +1/+1 counters on it.

Skarrg, the Rage Pits

{T}: Add {C}.
{R}{G}, {T}: Target creature gets +1/+1 and gains trample until end of turn.

Seeker of Skybreak

Savage Twister

Savage Twister deals X damage to each creature.

Hurricane

Hurricane deals X damage to each creature with flying and each player.

Gruul Locket

{T}: Add {R} or {G}.
{R/G}{R/G}{R/G}{R/G}, {T}, Sacrifice Gruul Locket: Draw two cards.

Kessig Wolf Run

{T}: Add {C}.
{X}{R}{G}, {T}: Target creature gets +X/+0 and gains trample until end of turn.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Devil's Play

Devil's Play deals X damage to any target.
Flashback {X}{R}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Polis Crusher

Trample, protection from enchantments
{4}{R}{G}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
Whenever Polis Crusher deals combat damage to a player, if Polis Crusher is monstrous, destroy target enchantment that player controls.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Reap the Past

Return X cards at random from your graveyard to your hand. Exile Reap the Past.

Unbound Flourishing

Whenever you cast a permanent spell with a mana cost that contains {X}, double the value of X.
Whenever you cast an instant or sorcery spell or activate an ability, if that spell's mana cost or that ability's activation cost contains {X}, copy that spell or ability. You may choose new targets for the copy.

Skarrg Guildmage

{R}{G}: Creatures you control gain trample until end of turn.
{1}{R}{G}: Target land you control becomes a 4/4 Elemental creature until end of turn. It's still a land.

Apocalypse Hydra

Apocalypse Hydra enters with X +1/+1 counters on it. If X is 5 or more, it enters with an additional X +1/+1 counters on it.
{1}{R}, Remove a +1/+1 counter from Apocalypse Hydra: It deals 1 damage to any target.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Hungering Hydra

Hungering Hydra enters with X +1/+1 counters on it.
Hungering Hydra can't be blocked by more than one creature.
Whenever Hungering Hydra is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)

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.

Flowstone Slide

All creatures get +X/-X until end of turn.

Arcane Signet

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

Nylea, God of the Hunt

Indestructible
As long as your devotion to green is less than five, Nylea isn't a creature. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)
Other creatures you control have trample.
{3}{G}: Target creature gets +2/+2 until end of turn.

Steel Hellkite

Flying
{2}: Steel Hellkite gets +1/+0 until end of turn.
{X}: Destroy each nonland permanent with mana value X whose controller was dealt combat damage by Steel Hellkite this turn. Activate only once each turn.

Lay of the Land

Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Fungal Reaches

{T}: Add {C}.
{1}, {T}: Put a storage counter on Fungal Reaches.
{1}, Remove X storage counters from Fungal Reaches: Add X mana in any combination of {R} and/or {G}.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Lifeblood Hydra

Trample
Lifeblood Hydra enters with X +1/+1 counters on it.
When Lifeblood Hydra dies, you gain life and draw cards equal to its power.

Magus of the Candelabra

Diligent Farmhand

{1}{G}, Sacrifice Diligent Farmhand: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
If Diligent Farmhand is in a graveyard, effects from spells named Muscle Burst count it as a card named Muscle Burst.

Forest

Overgrowth

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

Clan Defiance

Choose one or more —
• Clan Defiance deals X damage to target creature with flying.
• Clan Defiance deals X damage to target creature without flying.
• Clan Defiance deals X damage to target player or planeswalker.

Dangerous

All creatures able to block target creature this turn do so.
Fuse (You may cast one or both halves of this card from your hand.)

Armed

Target creature gets +1/+1 and gains double strike until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Armed // Dangerous

Silklash Spider

Reach
{X}{G}{G}: Silklash Spider deals X damage to each creature with flying.

Savageborn Hydra

Double strike
Savageborn Hydra enters with X +1/+1 counters on it.
{1}{R/G}: Put a +1/+1 counter on Savageborn Hydra. Activate only as a sorcery.

Harmonize

Blasphemous Act

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

Street Spasm

Street Spasm deals X damage to target creature without flying you don't control.
Overload {X}{X}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")