Replacing

Izzet Boilerworks

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

Mistrise Village

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {U}.
{U}, {T}: The next spell you cast this turn can't be countered.

Have

Roaming Throne

Ward {2}
As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Astral Dragon

Flying
Project Image — When this creature enters, create two tokens that are copies of target noncreature permanent, except they're 3/3 Dragon creatures in addition to their other types, and they have flying.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Displacer Kitten

Avoidance — Whenever you cast a noncreature spell, exile up to one target nonland permanent you control, then return that card to the battlefield under its owner's control.

Temur Ascendancy

Creatures you control have haste.
Whenever a creature you control with power 4 or greater enters, you may draw a card.

Need Art

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.)

Blasphemous Act

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

Herald's Horn

As this artifact 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.

Dragon Tempest

Whenever a creature you control with flying enters, it gains haste until end of turn.
Whenever a Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.

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.

Simic Growth Chamber

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

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Gruul Turf

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

Lozhan, Dragons' Legacy

Flying
Whenever you cast an Adventure or Dragon spell, Lozhan deals damage equal to that spell's mana value to any target that isn't a commander.

Talisman of Impulse

{T}: Add {C}.
{T}: Add {R} or {G}. This artifact deals 1 damage to you.

Breeding Pool

({T}: Add {G} or {U}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Frontier Bivouac

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

Orb of Dragonkind

{1}, {T}: Add two mana in any combination of colors. Spend this mana only to cast Dragon spells or activate abilities of Dragons.
{R}, {T}, Sacrifice this artifact: Look at the top seven cards of your library. You may reveal a Dragon card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Twinflame Tyrant

Flying
If a source you control would deal damage to an opponent or a permanent an opponent controls, it deals double that damage instead.

Sol Ring

Roamer's Routine

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Harmonize {4}{G} (You may cast this card from your graveyard for its harmonize cost. You may tap a creature you control to reduce that cost by {X}, where X is its power. Then exile this spell.)

Stomping Ground

({T}: Add {R} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Stubborn Denial

Counter target noncreature spell unless its controller pays {1}.
Ferocious — If you control a creature with power 4 or greater, counter that spell instead.

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.

Genesis Ultimatum

Look at the top five cards of your library. Put any number of permanent cards from among them onto the battlefield and the rest into your hand. Exile Genesis Ultimatum.

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.

Dragonspeaker Shaman

Dragon spells you cast cost {2} less to cast.

Dragonmaster Outcast

At the beginning of your upkeep, if you control six or more lands, create a 5/5 red Dragon creature token with flying.

Chilling Screech

Counter target spell with mana value 2 or less. (Then shuffle this card into its owner's library.)

Runescale Stormbrood

Flying
Whenever you cast a noncreature spell or a Dragon spell, this creature gets +2/+0 until end of turn.

Runescale Stormbrood // Chilling Screech

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.

Korlessa, Scale Singer

You may look at the top card of your library any time.
You may cast Dragon spells from the top of your library.

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Dragon

Sarkhan, Dragonsoul

+2: Sarkhan deals 1 damage to each opponent and each creature your opponents control.
−3: Sarkhan deals 4 damage to target player or planeswalker.
−9: Search your library for any number of Dragon creature cards, put them onto the battlefield, then shuffle.

Counterspell

Dragonhawk, Fate's Tempest

Flying
Whenever Dragonhawk enters or attacks, exile the top X cards of your library, where X is the number of creatures you control with power 4 or greater. You may play those cards until your next end step. At the beginning of your next end step, Dragonhawk deals 2 damage to each opponent for each of those cards that are still exiled.

Temur Battlecrier

During your turn, spells you cast cost {1} less to cast for each creature you control with power 4 or greater.

Intet, the Dreamer

Flying
Whenever Intet deals combat damage to a player, you may pay {2}{U}. If you do, exile the top card of your library face down. You may look at that card for as long as it remains exiled. You may play that card without paying its mana cost for as long as Intet remains on the battlefield.

Earthquake

Earthquake deals X damage to each creature without flying and each player.

Goblin Anarchomancer

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

Izzet Signet

Draconic Muralists

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

Miirym, Sentinel Wyrm

Flying, ward {2}
Whenever another nontoken Dragon you control enters, create a token that's a copy of it, except the token isn't legendary.

Steam Vents

({T}: Add {U} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Magmaquake

Magmaquake deals X damage to each creature without flying and each planeswalker.

Ancient Silver Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. Draw cards equal to the result. You have no maximum hand size for the rest of the game.

Scourge of the Throne

Flying
Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Whenever this creature attacks for the first time each turn, if it's attacking the player with the most life or tied for most life, untap all attacking creatures. After this phase, there is an additional combat phase.

Island

Gruul Signet

Treasure

{T}, Sacrifice this token: Add one mana of any color.

Command Tower

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

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. This land deals 1 damage to you.

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.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Aetherize

Return all attacking creatures to their owner's hand.

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.

Wooded Foothills

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Simic Signet

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Secluded Courtyard

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

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.

Food

{2}, {T}, Sacrifice this token: You gain 3 life.

Old Gnawbone

Flying
Whenever a creature you control deals combat damage to a player, create that many Treasure tokens.

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.

Snakeskin Veil

Put a +1/+1 counter on target creature you control. It gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Lapis Orb of Dragonkind

{T}: Add {U}. When you spend this mana to cast a Dragon creature spell, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Arcane Signet

Atarka, World Render

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

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

The Great Henge

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{T}: Add {G}{G}. You gain 2 life.
Whenever a nontoken creature you control enters, put a +1/+1 counter on it and draw a card.

Dragonlord's Servant

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

Scalding Tarn

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Sarkhan, Soul Aflame

Dragon spells you cast cost {1} less to cast.
Whenever a Dragon you control enters, you may have Sarkhan become a copy of it until end of turn, except its name is Sarkhan, Soul Aflame and it's legendary in addition to its other types.

Renari, Merchant of Marvels

You may cast Dragon spells and artifact spells as though they had flash.
Choose a Background (You can have a Background as a second commander.)

Forest

Lathliss, Dragon Queen

Flying
Whenever another nontoken Dragon you control enters, create a 5/5 red Dragon creature token with flying.
{1}{R}: Dragons you control get +1/+0 until end of turn.

Ancient Bronze Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. When you do, put X +1/+1 counters on each of up to two target creatures, where X is the result.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Rapacious Dragon

Flying
When this creature enters, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Talisman of Curiosity

{T}: Add {C}.
{T}: Add {G} or {U}. This artifact deals 1 damage to you.

Mox Jasper

{T}: Add one mana of any color. Activate only if you control a Dragon.

Ureni of the Unwritten

Flying, trample
Whenever Ureni enters or attacks, look at the top eight cards of your library. You may put a Dragon creature card from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

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}.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Sokenzan, Crucible of Defiance

{T}: Add {R}.
Channel — {3}{R}, Discard this card: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Stormscale Scion

Flying
Other Dragons you control get +1/+1.
Storm (When you cast this spell, copy it for each spell cast before it this turn. Copies become tokens.)

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard this card: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you 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.

Rampant Growth

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

Maelstrom of the Spirit Dragon

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a Dragon spell or an Omen spell.
{4}, {T}, Sacrifice this land: Search your library for a Dragon card, reveal it, put it into your hand, then shuffle.

Kodama's Reach

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.

Mountain

Niv-Mizzet, Visionary

Flying
You have no maximum hand size.
Whenever a source you control deals noncombat damage to an opponent, you draw that many cards.

Mossfire Valley

Carnelian Orb of Dragonkind

{T}: Add {R}. If that mana is spent on a Dragon creature spell, it gains haste until end of turn.

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. This land deals 1 damage to you.

Balefire Dragon

Flying
Whenever this creature deals combat damage to a player, it deals that much damage to each creature that player controls.