Instrument of the Bards

At the beginning of your upkeep, you may put a harmony counter on Instrument of the Bards.
{3}{G}, {T}: Search your library for a creature card with mana value equal to the number of harmony counters on Instrument of the Bards, reveal it, and put it into your hand. If that card is legendary, create a Treasure token. Then shuffle.

Mountain

Atarka, World Render

Flying, trample
Whenever a Dragon you control attacks, it gains double strike until end of turn.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

Zetalpa, Primal Dawn

Flying, double strike, vigilance, trample, indestructible

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Gond Gate

Gates you control enter untapped.
{T}: Add {C}.
{T}: Add one mana of any color that a Gate you control could produce.

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.

Zilortha, Apex of Ikoria

Reach
For each non-Human creature you control, you may have that creature assign its combat damage as though it weren't blocked.

Invasion of Ikoria

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, search your library and/or graveyard for a non-Human creature card with mana value X or less and put it onto the battlefield. If you search your library this way, shuffle.

Invasion of Ikoria // Zilortha, Apex of Ikoria

Forest

Ragefire Hellkite

Flying
Whenever this creature attacks, you may sacrifice another creature. If you do, this creature gains double strike until end of turn.

Blossoming Sands

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {W}.

Harnessed Snubhorn

Vigilance
Whenever this creature deals combat damage to a player, return target artifact or enchantment card from your graveyard to the battlefield.

Rugged Highlands

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {R} or {G}.

Nesting Dragon

Flying
Landfall — Whenever a land you control enters, create a 0/2 red Dragon Egg creature token with defender and "When this token dies, create a 2/2 red Dragon creature token with flying and '{R}: This token gets +1/+0 until end of turn.'"

Kodama's Reach

Draconic Muralists

When this creature dies, you may search your library for a Dragon card, reveal it, put it into your hand, then shuffle.

Territorial Hammerskull

Whenever this creature attacks, tap target creature an opponent controls.

Zoological Study

Mill five cards, then return a creature card milled this way to your hand. (Then exile this card. You may cast the artifact later from exile.)

Monster Manual

{1}{G}, {T}: You may put a creature card from your hand onto the battlefield.

Monster Manual // Zoological Study

Baldur's Gate

{T}: Add {C}.
{2}, {T}: Add X mana of any one color, where X is the number of other Gates you control.

Explore the Underdark

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.
You take the initiative.

Red Dragon

Flying
Fire Breath — When this creature enters, it deals 4 damage to each opponent.

Terror of Mount Velus

Flying
Double strike (This creature deals both first-strike and regular combat damage.)
When this creature enters, creatures you control gain double strike until end of turn.

Terror of the Peaks

Flying
Spells your opponents cast that target this creature cost an additional 3 life to cast.
Whenever another creature you control enters, this creature deals damage equal to that creature's power to any target.

Alpine Meadow

({T}: Add {R} or {W}.)
This land enters tapped.

Camaraderie

You gain X life and draw X cards, where X is the number of creatures you control. Creatures you control get +1/+1 until end of turn.

Scourge of Valkas

Flying
Whenever this creature or another Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.
{R}: This creature gets +1/+0 until end of turn.

Atla Palani, Nest Tender

{2}, {T}: Create a 0/1 green Egg creature token with defender.
Whenever an Egg you control dies, reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.

Raging Regisaur

Whenever this creature attacks, it deals 1 damage to any target.

Dragon Arch

{2}, {T}: You may put a multicolored creature card from your hand onto the battlefield.

Dissonant Wave

Counter target activated or triggered ability from a noncreature source. (Then exile this card. You may cast the creature later from exile.)

Emerald Dragon

Emerald Dragon // Dissonant Wave

Pantlaza, Sun-Favored

Whenever Pantlaza or another Dinosaur you control enters, you may discover X, where X is that creature's toughness. Do this only once each turn. (Exile cards from the top of your library until you exile a nonland card with that mana value or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Ancient Imperiosaur

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Trample, ward {2}
This creature enters with two +1/+1 counters on it for each creature that convoked it.

Plains

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.)

Boros Guildgate

This land enters tapped.
{T}: Add {R} or {W}.

Cliffgate

This land enters tapped.
As this land enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Commune with Dinosaurs

Look at the top five cards of your library. You may reveal a Dinosaur or land card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Ghalta, Primal Hunger

This spell costs {X} less to cast, where X is the total power of creatures you control.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Belligerent Yearling

Trample
Whenever another Dinosaur you control enters, you may have this creature's base power become equal to that creature's power until end of turn.

Ghalta and Mavren

Trample
Whenever you attack, choose one —
• Create a tapped and attacking X/X green Dinosaur creature token with trample, where X is the greatest power among other attacking creatures.
• Create X 1/1 white Vampire creature tokens with lifelink, where X is the number of other attacking creatures.

Monsoon

At the beginning of each player's end step, tap all untapped Islands that player controls and this enchantment deals X damage to the player, where X is the number of Islands tapped this way.

Rith, the Awakener

Flying
Whenever Rith deals combat damage to a player, you may pay {2}{G}. If you do, choose a color, then create a 1/1 green Saproling creature token for each permanent of that color.

Etali, Primal Sickness

Trample, indestructible
Whenever Etali deals combat damage to a player, they get that many poison counters. (A player with ten or more poison counters loses the game.)

Etali, Primal Conqueror

Trample
When Etali enters, each player exiles cards from the top of their library until they exile a nonland card. You may cast any number of spells from among the nonland cards exiled this way without paying their mana costs.
{9}{G/P}: Transform Etali. Activate only as a sorcery.

Etali, Primal Conqueror // Etali, Primal Sickness

Imperial Aerosaur

Flying
When this creature enters, another target creature you control gets +1/+1 and gains flying until end of turn.

Fire Diamond

This artifact enters tapped.
{T}: Add {R}.

Crucible of Fire

Windbrisk Heights

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
This land enters tapped.
{T}: Add {W}.
{W}, {T}: You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.

Huatli's Raptor

Vigilance
When this creature enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Wind-Scarred Crag

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {R} or {W}.

Acolyte of Bahamut

Commander creatures you own have "The first Dragon spell you cast each turn costs {2} less to cast."

Sky Terror

Bloomwielder Dryads

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
At the beginning of your end step, put a +1/+1 counter on target creature you control.

Invasion of Moag

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, put a +1/+1 counter on each creature you control.

Invasion of Moag // Bloomwielder Dryads

Urban Daggertooth

Vigilance
Enrage — Whenever this creature is dealt damage, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Citadel Gate

This land enters tapped.
As this land enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Dragon's Hoard

Whenever a Dragon you control enters, put a gold counter on this artifact.
{T}, Remove a gold counter from this artifact: Draw a card.
{T}: Add one mana of any color.

Earthquake Dragon

This spell costs {X} less to cast, where X is the total mana value of Dragons you control.
Flying, trample
{2}{G}, Sacrifice a land: Return this card from your graveyard to your hand.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Commune with Nature

Look at the top five cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Brawn

Trample
As long as this card is in your graveyard and you control a Forest, creatures you control have trample.

Summoner's Egg

Imprint — When this creature enters, you may exile a card from your hand face down.
When this creature dies, turn the exiled card face up. If it's a creature card, put it onto the battlefield under your control.

Overgrown Armasaur

Enrage — Whenever this creature is dealt damage, create a 1/1 green Saproling creature token.

Gishath, Sun's Avatar

Vigilance, trample, haste
Whenever Gishath deals combat damage to a player, reveal that many cards from the top of your library. Put any number of Dinosaur creature cards from among them onto the battlefield and the rest on the bottom of your library in a random order.

Gavony Township

{T}: Add {C}.
{2}{G}{W}, {T}: Put a +1/+1 counter on each creature you control.

Forktail Sweep

Forktail Sweep deals 1 damage to each creature you don't control. (Then exile this card. You may cast the creature later from exile.)

Fang Dragon

Fang Dragon // Forktail Sweep

Atraxa's Fall

Destroy target artifact, battle, enchantment, or creature with flying.

Adult Gold Dragon

Mosswort Bridge

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
This land enters tapped.
{T}: Add {G}.
{G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

Jungle Shrine

This land enters tapped.
{T}: Add {R}, {G}, or {W}.

Zacama, Primal Calamity

Vigilance, reach, trample
When Zacama enters, if you cast it, untap all lands you control.
{2}{R}: Zacama deals 3 damage to target creature.
{2}{G}: Destroy target artifact or enchantment.
{2}{W}: You gain 3 life.

Belligerent Regisaur

Trample
Whenever you cast a spell, this creature gains indestructible until end of turn.

Invasion of Ixalan

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, look at the top five cards of your library. You may reveal a permanent card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Invasion of Ixalan // Belligerent Regisaur

Bellowing Aegisaur

Enrage — Whenever this creature is dealt damage, put a +1/+1 counter on each other creature you control.

Dragonlord's Servant

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

Soaring Sandwing

Flying
When this creature enters, you gain 3 life.
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Manor Gate

This land enters tapped.
As this land enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Boil

Basri's Solidarity

Put a +1/+1 counter on each creature you control.

Ancient Copper Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. You create a number of Treasure tokens equal to the result.

Ashmouth Dragon

Flying
Whenever you cast an instant or sorcery spell, this creature deals 2 damage to any target.

Smoldering Egg

Defender
Whenever you cast an instant or sorcery spell, put a number of ember counters on this creature equal to the amount of mana spent to cast that spell. Then if this creature has seven or more ember counters on it, remove them and transform this creature.

Smoldering Egg // Ashmouth Dragon

Gruul Signet

Demanding Dragon

Flying
When this creature enters, it deals 5 damage to target opponent unless that player sacrifices a creature of their choice.

Colossadactyl

Charging Tuskodon

Trample
If this creature would deal combat damage to a player, it deals double that damage to that player instead.

Ganax, Astral Hunter

Flying
Whenever Ganax or another Dragon you control enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Choose a Background (You can have a Background as a second commander.)

Moss Diamond

This artifact enters tapped.
{T}: Add {G}.

Belligerent Brontodon

Each creature you control assigns combat damage equal to its toughness rather than its power.

Lightning Greaves

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

Descendants' Path

At the beginning of your upkeep, reveal the top card of your library. If it's a creature card that shares a creature type with a creature you control, you may cast it without paying its mana cost. If you don't cast it, put it on the bottom of your library.