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.)

Island

Gemhide Sliver

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

Quick Sliver

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

Herald's Horn

As Herald's Horn 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.

Spara's Headquarters

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

Sliver Hivelord

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

Demonic Tutor

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

Tempered Sliver

Sliver creatures you control have "Whenever this creature deals combat damage to a player, put a +1/+1 counter on it."

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.")

Izzet Signet

Rakdos Signet

Blasphemous Act

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

Orzhov Signet

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Plateau

Urza's Incubator

As Urza's Incubator enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Sol Ring

Galerider Sliver

Sliver creatures you control have flying.

Boros Signet

Counterspell

Brood Sliver

Whenever a Sliver deals combat damage to a player, its controller may create a 1/1 colorless Sliver creature token.

Scrubland

Forest

Command Tower

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

Syphon Sliver

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

Secluded Courtyard

As Secluded Courtyard 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.

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

Golgari Signet

Coat of Arms

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

Harmonic Sliver

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

Shifting Sliver

Slivers can't be blocked except by Slivers.

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: 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.

Plains

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.

Manalith

Leeching Sliver

Whenever a Sliver you control attacks, defending player loses 1 life.

Talon Sliver

Badlands

Savannah

Sentinel Sliver

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

Swamp

Taiga

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.

Volcanic Island

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.)

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.)

Selesnya Signet

Screeching Sliver

All Slivers have "{T}: Target player mills a card."

Negate

Savage Lands

Savage Lands enters tapped.
{T}: Add {B}, {R}, or {G}.

Sliver Legion

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

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}.

Virulent Sliver

All Sliver creatures have poisonous 1. (Whenever a Sliver deals combat damage to a player, that player gets a poison counter. A player with ten or more poison counters loses the game.)

Striking Sliver

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

Groundshaker Sliver

Sliver creatures you control have trample. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)

Door of Destinies

As Door of Destinies enters, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.
Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

Crystalline Sliver

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

Dregscape Sliver

Each Sliver creature card in your graveyard has unearth {2}.
Unearth {2} ({2}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Shadow Sliver

All Sliver creatures have shadow. (They can block or be blocked by only creatures with shadow.)

Jetmir's Garden

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

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.

Acidic Sliver

All Slivers have "{2}, Sacrifice this permanent: This permanent deals 2 damage to any target."

Blur Sliver

Sliver creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Raffine's Tower

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

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne 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.

Simic Signet

Bayou

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.)

Hive Stirrings

Create two 1/1 colorless Sliver creature tokens.

Scuttling Sliver

Sliver creatures you control have "{2}: Untap this creature."

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.

Belligerent Sliver

Sliver creatures you control have menace. (They can't be blocked except by two or more creatures.)

Dimir Signet

Constricting Sliver

Sliver creatures you control have "When this creature enters, you may exile target creature an opponent controls until this creature leaves the battlefield."

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Cleaving Sliver

Pillar of Origins

As Pillar of Origins enters, choose a creature type.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Predatory Sliver

Vampiric Tutor

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

Arcane Signet

Tropical Island

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.

Pulmonic Sliver

All Sliver creatures have flying.
All Slivers have "If this permanent would be put into a graveyard, you may put it on top of its owner's library instead."

Gruul Signet

Mountain

Tundra

Icon of Ancestry

As Icon of Ancestry enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Sidewinder Sliver

All Sliver creatures have flanking. (Whenever a creature without flanking blocks a Sliver, the blocking creature gets -1/-1 until end of turn.)

Azorius Signet

Opaline Sliver

All Slivers have "Whenever this permanent becomes the target of a spell an opponent controls, you may draw a card."

Two-Headed Sliver

All Sliver creatures have menace. (They can't be blocked except by two or more creatures.)