Clot Sliver

All Slivers have "{2}: Regenerate this permanent."

Counterspell

Mnemonic Sliver

All Slivers have "{2}, Sacrifice this permanent: Draw a card."

Ertai's Meddling

X can't be 0.
Target spell's controller exiles it with X delay counters on it.
At the beginning of each of that player's upkeeps, if that card is exiled, remove a delay counter from it. If the card has no delay counters on it, the player puts it onto the stack as a copy of the original spell.

Lobotomy

Target player reveals their hand, then you choose a card other than a basic land card from it. Search that player's graveyard, hand, and library for all cards with the same name as the chosen card and exile them. Then that player shuffles.

Evincar's Justice

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Evincar's Justice deals 2 damage to each creature and each player.

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Metallic Sliver

Diabolic Edict

Target player sacrifices a creature of their choice.

Swamp

Dismiss

Rootwater Depths

{T}: Add {C}.
{T}: Add {U} or {B}. This land doesn't untap during your next untap step.

Vampiric Sliver

All Sliver creatures have "Whenever a creature dealt damage by this creature this turn dies, put a +1/+1 counter on this creature."

Synchronous Sliver

Winged Sliver

Spitting Sliver

Shadow Sliver

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

Dark Banishing

Destroy target nonblack creature. It can't be regenerated.

Shifting Sliver

Slivers can't be blocked except by Slivers.

Essence Bottle

{3}, {T}: Put an elixir counter on this artifact.
{T}, Remove all elixir counters from this artifact: You gain 2 life for each elixir counter removed this way.

Fevered Convulsions

{2}{B}{B}: Put a -1/-1 counter on target creature.

Telekinetic Sliver

All Slivers have "{T}: Tap target permanent."

Island

Leeching Sliver

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

Dream Cache

Draw three cards, then put two cards from your hand both on top of your library or both on the bottom of your library.

Whispers of the Muse

Buyback {5} (You may pay an additional {5} as you cast this spell. If you do, put this card into your hand as it resolves.)
Draw a card.

Spell Blast

Counter target spell with mana value X. (For example, if that spell's mana cost is {3}{U}{U}, X is 5.)