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."

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon 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.

Heart Sliver

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.)

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."

Blur Sliver

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

Biomancer's Familiar

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.
{T}: The next time target creature adapts this turn, it adapts as though it had no +1/+1 counters on it.

Crystalline Sliver

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

Predatory Sliver

Sliver Legion

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

Arcane Signet

{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.)

Might Sliver

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.

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.

Megantic Sliver

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.)

Gemhide Sliver

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

Manaweft Sliver

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

Thorncaster Sliver

Sliver creatures you control have "Whenever this creature attacks, it deals 1 damage to any target."

Harmonic Sliver

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

Striking Sliver

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

Quick Sliver

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

Sentinel Sliver

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

Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Sol Ring

Chromatic Lantern

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

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.)

Battle 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.

Sliver Hivelord

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

Leeching Sliver

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

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.)