Jegantha, the Wellspring

Companion — No card in your starting deck has more than one of the same mana symbol in its mana cost. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
{T}: Add {W}{U}{B}{R}{G}. This mana can't be spent to pay generic mana costs.

Arcane Signet

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

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.)

Ghostflame Sliver

Prismatic Vista

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Taiga

Quick Sliver

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

Syphon Sliver

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

Temple Garden

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

Hibernation Sliver

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

Mountain

Ward Sliver

As Ward Sliver enters, choose a color.
All Slivers have protection from the chosen color.

Forest

Shifting Sliver

Slivers can't be blocked except by Slivers.

Search for Tomorrow

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Suspend 2—{G} (Rather than cast this card from your hand, you may pay {G} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Nature's Lore

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

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.

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.)

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Opaline Sliver

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

Harmonic Sliver

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

Quilled Sliver

All Slivers have "{T}: This permanent deals 1 damage to target attacking or blocking creature."

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.

Brood Sliver

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

Winged Sliver

Godless Shrine

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

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Sentinel Sliver

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

Farseek

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

Heroic Intervention

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

Striking Sliver

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

Bring to Light

Converge — Search your library for a creature, instant, or sorcery card with mana value less than or equal to the number of colors of mana spent to cast this spell, exile that card, then shuffle. You may cast that card without paying its mana cost.

Three Visits

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

Sliver Hivelord

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

Fellwar Stone

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Gemhide Sliver

All Slivers have "{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.)

Sol Ring

Sliver Queen

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

Chromatic Lantern

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

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}.

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

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.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

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.

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."

Coalition Relic

{T}: Add one mana of any color.
{T}: Put a charge counter on Coalition Relic.
At the beginning of your first main phase, remove all charge counters from Coalition Relic. Add one mana of any color for each charge counter removed this way.

Sliver Legion

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

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.

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.

Spinneret Sliver

Mana Confluence

{T}, Pay 1 life: Add one mana of any color.

Island

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.

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.

Galerider Sliver

Sliver creatures you control have flying.

Hive Stirrings

Create two 1/1 colorless Sliver creature tokens.

Mirari's Wake

Creatures you control get +1/+1.
Whenever you tap a land for mana, add one mana of any type that land produced.

Plains

Clot Sliver

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

Demonic Tutor

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

Muscle Sliver

Swamp

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.

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Predatory Sliver

Breeding Pool

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

Unclaimed Territory

As Unclaimed Territory 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.

Heart Sliver

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Cultivate

Manaweft Sliver

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

Bayou

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.

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Forbidden Orchard

{T}: Add one mana of any color.
Whenever you tap Forbidden Orchard for mana, target opponent creates a 1/1 colorless Spirit creature token.

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.

Bonescythe Sliver

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

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.

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.

Necrotic Sliver

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

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.

Crystalline Sliver

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

Synapse Sliver

Whenever a Sliver deals combat damage to a player, its controller may draw a card.

Hunter Sliver

All Sliver creatures have provoke. (Whenever a Sliver attacks, its controller may have target creature defending player controls untap and block it if able.)

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.

Birds of Paradise

Realmwalker

Changeling (This card is every creature type.)
As Realmwalker enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Sinew Sliver

Plated 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.)

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.