Vorinclex, Monstrous Raider

Trample, haste
If you would put one or more counters on a permanent or player, put twice that many of each of those kinds of counters on that permanent or player instead.
If an opponent would put one or more counters on a permanent or player, they put half that many of each of those kinds of counters on that permanent or player instead, rounded down.

Red Sun's Zenith

Red Sun's Zenith deals X damage to any target. If a creature dealt damage this way would die this turn, exile it instead. Shuffle Red Sun's Zenith into its owner's library.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

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 this creature becomes monstrous, create X X/X green Hydra creature tokens.

Shivan Devastator

Flying, haste
This creature enters with X +1/+1 counters on it.

Elvish Mystic

Cinder Glade

({T}: Add {R} or {G}.)
This land enters tapped unless you control two or more basic lands.

Branching Evolution

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.

Mage Slayer

Whenever equipped creature attacks, it deals damage equal to its power to the player or planeswalker it's attacking.
Equip {3}

Delete

Delete deals X damage to each nonartifact creature and each player.

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Reiterate

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Copy target instant or sorcery spell. You may choose new targets for the copy.

Nyxbloom Ancient

Trample
If you tap a permanent for mana, it produces three times as much of that mana instead.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Gargos, Vicious Watcher

Vigilance
Hydra spells you cast cost {4} less to cast.
Whenever a creature you control becomes the target of a spell, Gargos fights up to one target creature you don't control.

Pyromancer's Goggles

{T}: Add {R}. When that mana is spent to cast a red instant or sorcery spell, copy that spell and you may choose new targets for the copy.

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.

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.

Thought Vessel

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.

Ozolith, the Shattered Spire

If one or more +1/+1 counters would be put on an artifact or creature you control, that many plus one +1/+1 counters are put on it instead.
{1}{G}, {T}: Put a +1/+1 counter on target artifact or creature you control. Activate only as a sorcery.
Cycling {2} ({2}, Discard this card: Draw a card.)

Harmonize

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.

Bonfire of the Damned

Bonfire of the Damned deals X damage to target player or planeswalker and each creature that player or that planeswalker's controller controls.
Miracle {X}{R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

All Will Be One

Whenever you put one or more counters on a permanent or player, this enchantment deals that much damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.

Fiery Emancipation

If a source you control would deal damage to a permanent or player, it deals triple that damage to that permanent or player instead.

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Awaken the Woods

Create X 1/1 green Forest Dryad land creature tokens. (They're affected by summoning sickness.)

Hooded Hydra

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

Patriar's Seal

{T}: Add one mana of any color.
{1}, {T}: Untap target legendary creature you control.

Garruk's Uprising

When this enchantment enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever a creature you control with power 4 or greater enters, draw a card.

Banefire

Banefire deals X damage to any target.
If X is 5 or more, this spell can't be countered and the damage can't be prevented.

Apocalypse Hydra

This creature 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 this creature: It deals 1 damage to any target.

Stonecoil Serpent

Reach, trample, protection from multicolored
This creature enters with X +1/+1 counters on it.

Mountain

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.

Mana Reflection

If you tap a permanent for mana, it produces twice as much of that mana instead.

Nexos

Strategic Coordinator — Basic lands you control have "{T}: Add {C}{C}. Spend this mana only on costs that contain {X}."

Gruul Signet

Primordial Hydra

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

Sol Ring

Basalt Monolith

This artifact doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap this artifact.

Rockfall Vale

This land enters tapped unless you control two or more other lands.
{T}: Add {R} or {G}.

Arcane Signet

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

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Walking Ballista

This creature enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on this creature.
Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Valakut Stoneforge

Valakut Awakening

Put any number of cards from your hand on the bottom of your library, then draw that many cards plus one.

Valakut Awakening // Valakut Stoneforge

Domri Rade

+1: Look at the top card of your library. If it's a creature card, you may reveal it and put it into your hand.
−2: Target creature you control fights another target creature.
−7: You get an emblem with "Creatures you control have double strike, trample, hexproof, and haste."

Blasphemous Act

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

Steelbane Hydra

This creature enters with X +1/+1 counters on it.
{2}{G}, Remove a +1/+1 counter from this creature: Destroy target artifact or enchantment.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Kodama's Reach

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.

Gruul Turf

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Traverse the Outlands

Search your library for up to X basic land cards, where X is the greatest power among creatures you control. Put those cards onto the battlefield tapped, then shuffle.

Lifeblood Hydra

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

Vigor

Trample
If damage would be dealt to another creature you control, prevent that damage. Put a +1/+1 counter on that creature for each 1 damage prevented this way.
When Vigor is put into a graveyard from anywhere, shuffle it into its owner's library.

The Red Terror

Advanced Species — Whenever a red source you control deals damage to one or more permanents and/or players, put a +1/+1 counter on The Red Terror.

Game Trail

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

Voracious Hydra

Trample
This creature enters with X +1/+1 counters on it.
When this creature enters, choose one —
• Double the number of +1/+1 counters on this creature.
• This creature fights target creature you don't control.

Savage Ventmaw

Flying
Whenever this creature attacks, add {R}{R}{R}{G}{G}{G}. Until end of turn, you don't lose this mana as steps and phases end.

Command Tower

The Ozolith

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith.
At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

Genesis Wave

Reveal the top X cards of your library. You may put any number of permanent cards with mana value X or less from among them onto the battlefield. Then put all cards revealed this way that weren't put onto the battlefield into your graveyard.

Hungering Hydra

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

Elementalist's Palette

Whenever you cast a spell with {X} in its mana cost, put two charge counters on this artifact.
{T}: Add one mana of any color.
{T}: Add {C} for each charge counter on this artifact. Spend this mana only on costs that contain {X}.

Up the Beanstalk

When this enchantment enters and whenever you cast a spell with mana value 5 or greater, draw a card.

Savageborn Hydra

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

Rosheen Meanderer

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

Forest

Rootbound Crag

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Shatterskull, the Hammer Pass

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {R}.

Shatterskull Smashing

Shatterskull Smashing deals X damage divided as you choose among up to two target creatures and/or planeswalkers. If X is 6 or more, Shatterskull Smashing deals twice X damage divided as you choose among them instead.

Shatterskull Smashing // Shatterskull, the Hammer Pass

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.