Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon, the Boundless enters, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.

Arcane Signet

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

Sacred Foundry

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

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Jetmir's Garden

({T}: Add {R}, {G}, or {W}.)
Jetmir's Garden enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Timeless Lotus

Timeless Lotus enters tapped.
{T}: Add {W}{U}{B}{R}{G}.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Arid Mesa

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

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Hibernation Sliver

All Slivers have "Pay 2 life: Return this permanent to its owner's hand."

Ziatora's Proving Ground

({T}: Add {B}, {R}, or {G}.)
Ziatora's Proving Ground enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Syphon Sliver

Sliver creatures you control have lifelink. (Damage dealt by a Sliver creature you control also causes you to gain that much life.)

Gemhide Sliver

All Slivers have "{T}: Add one mana of any color."

Galerider Sliver

Sliver creatures you control have flying.

Lazotep Sliver

Sliver creatures you control have afflict 2. (Whenever a creature with afflict 2 becomes blocked, defending player loses 2 life.)
Whenever a nontoken Sliver you control dies, amass Slivers 2. (Put two +1/+1 counters on an Army you control. It's also a Sliver. If you don't control an Army, create a 0/0 black Sliver Army creature token first.)

Savai Triome

({T}: Add {R}, {W}, or {B}.)
Savai Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Patchwork Banner

As Patchwork Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Imperial Seal

Raffine's Tower

({T}: Add {W}, {U}, or {B}.)
Raffine's Tower enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Polluted Delta

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

And They Shall Know No Fear

Choose a creature type. Creatures you control of the chosen type get +1/+0 and gain indestructible until end of turn.

Three Visits

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

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

The World Tree

The World Tree enters tapped.
{T}: Add {G}.
As long as you control six or more lands, lands you control have "{T}: Add one mana of any color."
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice The World Tree: Search your library for any number of God cards, put them onto the battlefield, then shuffle.

Temple Garden

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

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Bloodstained Mire

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

Misty Rainforest

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

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.")

Horned Sliver

Indatha Triome

({T}: Add {W}, {B}, or {G}.)
Indatha Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Overgrown Tomb

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

Sinew Sliver

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Muscle Sliver

Hatchery Sliver

Replicate {1}{G} (When you cast this spell, copy it for each time you paid its replicate cost.)
Each Sliver spell you cast has replicate. The replicate cost is equal to its mana cost. (A copy of a permanent spell becomes a token.)

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.

Sliver Hivelord

Sliver creatures you control have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Survival of the Fittest

{G}, Discard a creature card: Search your library for a creature card, reveal that card, put it into your hand, then shuffle.

Crystalline Sliver

All Slivers have shroud. (They can't be the targets of spells or abilities.)

Flooded Strand

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

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Anguished Unmaking

Exile target nonland permanent. You lose 3 life.

Breeding Pool

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

Command Tower

Manaweft Sliver

Sliver creatures you control have "{T}: Add one mana of any color."

Steam Vents

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

Ketria Triome

({T}: Add {G}, {U}, or {R}.)
Ketria Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Scalding Tarn

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

Xander's Lounge

({T}: Add {U}, {B}, or {R}.)
Xander's Lounge enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Spara's Headquarters

({T}: Add {G}, {W}, or {U}.)
Spara's Headquarters enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Verdant Catacombs

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

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.

Food Chain

Exile a creature you control: Add X mana of any one color, where X is 1 plus the exiled creature's mana value. Spend this mana only to cast creature spells.

Raugrin Triome

({T}: Add {U}, {R}, or {W}.)
Raugrin Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

Farseek

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

Blood Crypt

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

Counterspell

Kindred Summons

Choose a creature type. Reveal cards from the top of your library until you reveal X creature cards of the chosen type, where X is the number of creatures you control of that type. Put those cards onto the battlefield, then shuffle the rest of the revealed cards into your library.

Sliver Hive

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a Sliver spell.
{5}, {T}: Create a 1/1 colorless Sliver creature token. Activate only if you control a Sliver.

Heart Sliver

Chromatic Orrery

You may spend mana as though it were mana of any color.
{T}: Add {C}{C}{C}{C}{C}.
{5}, {T}: Draw a card for each color among permanents you control.

Striking Sliver

Sliver creatures you control have first strike. (They deal combat damage before creatures without first strike.)

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Patriarch's Bidding

Each player chooses a creature type. Each player returns all creature cards of a type chosen this way from their graveyard to the battlefield.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Watery Grave

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

The First Sliver

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Sliver spells you cast have cascade.

Wooded Foothills

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

Cavern of Souls

As Cavern of Souls 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, and that spell can't be countered.

Spiteful Sliver

Sliver creatures you control have "Whenever this creature is dealt damage, it deals that much damage to target player or planeswalker."

Marsh Flats

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Quick Sliver

Flash
Any player may cast Sliver spells as though they had flash.

Necrotic Sliver

All Slivers have "{3}, Sacrifice this permanent: Destroy target permanent."

Godless Shrine

({T}: Add {W} or {B}.)
As Godless Shrine enters, you may pay 2 life. If you don't, it enters tapped.

Reflections of Littjara

As Reflections of Littjara enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Shifting Sliver

Slivers can't be blocked except by Slivers.

Lavabelly Sliver

Sliver creatures you control have "When this creature enters, it deals 1 damage to target player or planeswalker and you gain 1 life."

Bonescythe Sliver

Sliver creatures you control have double strike. (They deal both first-strike and regular combat damage.)

Harmonic Sliver

All Slivers have "When this permanent enters, destroy target artifact or enchantment."

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.

Predatory Sliver

Sentinel Sliver

Sliver creatures you control have vigilance. (Attacking doesn't cause them to tap.)

Sliver Overlord

{3}: Search your library for a Sliver card, reveal that card, put it into your hand, then shuffle.
{3}: Gain control of target Sliver. (This effect lasts indefinitely.)

Sliver Gravemother

The "legend rule" doesn't apply to Slivers you control.
Each Sliver creature card in your graveyard has encore {X}, where X is its mana value.
Encore {5} ({5}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Stomping Ground

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

Nature's Lore

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

Hallowed Fountain

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

Diffusion Sliver

Whenever a Sliver creature you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {2}.

Gaea's Cradle

{T}: Add {G} for each creature you control.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Root Sliver

This spell can't be countered.
Sliver spells can't be countered.

Venom Sliver

Sliver creatures you control have deathtouch. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

Sliver Legion

All Sliver creatures get +1/+1 for each other Sliver on the battlefield.

Windswept Heath

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