Chittering Harvester

Mutate {4}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, each opponent sacrifices a creature of their choice.

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.)

Vadrok, Apex of Thunder

Mutate {1}{W/U}{R}{R} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying, first strike
Whenever this creature mutates, you may cast target noncreature card with mana value 3 or less from your graveyard without paying its mana cost.

Mountain

Sliver Legion

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

Island

Shifting Sliver

Slivers can't be blocked except by Slivers.

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Sword of Feast and Famine

Equipped creature gets +2/+2 and has protection from black and from green.
Whenever equipped creature deals combat damage to a player, that player discards a card and you untap all lands you control.
Equip {2}

Diabolic Tutor

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

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.

Swamp

Sliver Hivelord

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

Heart Sliver

Opaline Sliver

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

Glowstone Recluse

Mutate {3}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Reach
Whenever this creature mutates, put two +1/+1 counters on it.

Brood Sliver

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

Necropanther

Mutate {2}{W/B}{W/B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, return target creature card with mana value 3 or less from your graveyard to the battlefield.

Hollowhead Sliver

Sliver creatures you control have "{T}, Discard a card: Draw a card."

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Blur Sliver

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

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.)

Two-Headed Sliver

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

Sentinel Sliver

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

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.)

Gemhide Sliver

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

Wings of Velis Vel

Changeling (This card is every creature type.)
Until end of turn, target creature has base power and toughness 4/4, gains all creature types, and gains flying.

Chromatic Lantern

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

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.)

Plains

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.

Boneyard Lurker

Mutate {2}{B/G}{B/G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, return target permanent card from your graveyard to your hand.

Harmonic Sliver

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

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Nethroi, Apex of Death

Mutate {4}{G/W}{B}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Deathtouch, lifelink
Whenever this creature mutates, return any number of target creature cards with total power 10 or less from your graveyard to the battlefield.

Homing Sliver

Each Sliver card in each player's hand has slivercycling {3}.
Slivercycling {3} ({3}, Discard this card: Search your library for a Sliver card, reveal it, put it into your hand, then shuffle.)

Belligerent Sliver

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

Illuna, Apex of Wishes

Mutate {3}{R/G}{U}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying, trample
Whenever this creature mutates, exile cards from the top of your library until you exile a nonland permanent card. Put that card onto the battlefield or into your hand.

Galerider Sliver

Sliver creatures you control have flying.

Brokkos, Apex of Forever

Mutate {2}{U/B}{G}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Trample
You may cast Brokkos, Apex of Forever from your graveyard using its mutate ability.

Dormant Sliver

All Sliver creatures have defender.
All Slivers have "When this permanent enters, draw a card."

Sliver Queen

{2}: Create a 1/1 colorless Sliver creature token.

Demonic Tutor

Shields of Velis Vel

Changeling (This card is every creature type.)
Creatures target player controls get +0/+1 and gain all creature types until end of turn.

Sol Ring

Forest

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.

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Otrimi, the Ever-Playful

Mutate {1}{B}{G}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Trample
Whenever this creature deals combat damage to a player, return target creature card with mutate from your graveyard to your hand.

Striking Sliver

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

Spinneret Sliver

Crystalline Sliver

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

Souvenir Snatcher

Mutate {5}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying
Whenever this creature mutates, gain control of target noncreature artifact.

Manaweft Sliver

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

Syphon Sliver

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

Ur-Golem's Eye

Horned Sliver

Gemrazer

Mutate {1}{G}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Reach, trample
Whenever this creature mutates, destroy target artifact or enchantment an opponent controls.

Talon Sliver

Snapdax, Apex of the Hunt

Mutate {2}{B/R}{W}{W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Double strike
Whenever this creature mutates, it deals 4 damage to target creature or planeswalker an opponent controls and you gain 4 life.

Nicol Bolas, the Arisen

+2: Draw two cards.
−3: Nicol Bolas, the Arisen deals 10 damage to target creature or planeswalker.
−4: Put target creature or planeswalker card from a graveyard onto the battlefield under your control.
−12: Exile all but the bottom card of target player's library.

Nicol Bolas, the Ravager

Flying
When Nicol Bolas, the Ravager enters, each opponent discards a card.
{4}{U}{B}{R}: Exile Nicol Bolas, the Ravager, then return him to the battlefield transformed under his owner's control. Activate only as a sorcery.

Nicol Bolas, the Ravager // Nicol Bolas, the Arisen

Fury Sliver

Darkheart Sliver

All Slivers have "Sacrifice this permanent: You gain 3 life."

Shadow Sliver

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

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.