Basal Sliver

All Slivers have "Sacrifice this permanent: Add {B}{B}."

Sliver Hivelord

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

Krallenhorde Howler

Creature spells you cast cost {1} less to cast.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Krallenhorde Howler.

Duskwatch Recruiter

{2}{G}: Look at the top three cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
At the beginning of each upkeep, if no spells were cast last turn, transform Duskwatch Recruiter.

Duskwatch Recruiter // Krallenhorde Howler

Breeding Pool

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

Indatha Triome

({T}: Add {W}, {B}, or {G}.)
Indatha Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Farseek

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

Godless Shrine

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

Rukarumel, Biologist

As Rukarumel, Biologist enters, choose a creature type.
Slivers you control and nontoken creatures you control are the chosen type in addition to their other creature types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 1/1 colorless Sliver creature token.

Heroic Intervention

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

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.

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.

Blossom-Clad Werewolf

{T}: Add two mana of any one color.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Weaver of Blossoms

{T}: Add one mana of any color.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Weaver of Blossoms // Blossom-Clad Werewolf

Blur Sliver

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

Brood Sliver

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

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Aura Shards

Whenever a creature you control enters, you may destroy target artifact or enchantment.

Distant Melody

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

Bad River

Bad River enters tapped.
{T}, Sacrifice Bad River: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Werewolf of Ancient Hunger

Vigilance, trample
Werewolf of Ancient Hunger's power and toughness are each equal to the total number of cards in all players' hands.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Werewolf of Ancient Hunger.

Sage of Ancient Lore

Sage of Ancient Lore's power and toughness are each equal to the number of cards in your hand.
When Sage of Ancient Lore enters, draw a card.
At the beginning of each upkeep, if no spells were cast last turn, transform Sage of Ancient Lore.

Sage of Ancient Lore // Werewolf of Ancient Hunger

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Shifting Sliver

Slivers can't be blocked except by Slivers.

Conduit of Emrakul

Whenever Conduit of Emrakul attacks, add {C}{C} at the beginning of your next main phase this turn.

Conduit of Storms

Whenever Conduit of Storms attacks, add {R} at the beginning of your next main phase this turn.
{3}{R}{R}: Transform Conduit of Storms.

Conduit of Storms // Conduit of Emrakul

Bloom Tender

{T}: For each color among permanents you control, add one mana of that color.

Cryptolith Rite

Creatures you control have "{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}.

Lancer Sliver

Sliver creatures you control have first strike.

Exotic Orchard

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

Temple Garden

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

Swamp

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.

Crypt Sliver

All Slivers have "{T}: Regenerate target Sliver."

Grasslands

Grasslands enters tapped.
{T}, Sacrifice Grasslands: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Tovolar, the Midnight Scourge

Whenever a Wolf or Werewolf you control deals combat damage to a player, draw a card.
{X}{R}{G}: Target Wolf or Werewolf you control gets +X/+0 and gains trample until end of turn.
Nightbound

Tovolar, Dire Overlord

Whenever a Wolf or Werewolf you control deals combat damage to a player, draw a card.
At the beginning of your upkeep, if you control three or more Wolves and/or Werewolves, it becomes night. Then transform any number of Human Werewolves you control.
Daybound

Tovolar, Dire Overlord // Tovolar, the Midnight Scourge

Howling Chorus

Creatures with power less than Howling Chorus's power can't block it.
Whenever Howling Chorus deals combat damage to a player, create a 3/2 colorless Eldrazi Horror creature token.

Shrill Howler

Creatures with power less than Shrill Howler's power can't block it.
{5}{G}: Transform Shrill Howler.

Shrill Howler // Howling Chorus

Manaweft Sliver

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

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.

Abaddon the Despoiler

Trample
Mark of Chaos Ascendant — During your turn, spells you cast from your hand with mana value X or less have cascade, where X is the total amount of life your opponents have lost this turn.

Rocky Tar Pit

Rocky Tar Pit enters tapped.
{T}, Sacrifice Rocky Tar Pit: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Sinuous Predator

Sinuous Predator can't be blocked by more than one creature.

Kessig Prowler

Kessig Prowler // Sinuous Predator

Syphon Sliver

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

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.)

Nightfall Predator

{R}, {T}: Nightfall Predator fights target creature. (Each deals damage equal to its power to the other.)
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Nightfall Predator.

Daybreak Ranger

{T}: Daybreak Ranger deals 2 damage to target creature with flying.
At the beginning of each upkeep, if no spells were cast last turn, transform Daybreak Ranger.

Daybreak Ranger // Nightfall Predator

Striking Sliver

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

Frenzied Trapbreaker

{1}, Sacrifice Frenzied Trapbreaker: Destroy target artifact or enchantment.
Whenever Frenzied Trapbreaker attacks, destroy target artifact or enchantment defending player controls.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Outland Liberator

{1}, Sacrifice Outland Liberator: Destroy target artifact or enchantment.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Outland Liberator // Frenzied Trapbreaker

Wildsong Howler

Whenever this creature enters or transforms into Wildsong Howler, look at the top six cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Howlpack Piper

This spell can't be countered.
{1}{G}, {T}: You may put a creature card from your hand onto the battlefield. If it's a Wolf or Werewolf, untap Howlpack Piper. Activate only as a sorcery.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Howlpack Piper // Wildsong Howler

Hollowhead Sliver

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

Bonders' Enclave

{T}: Add {C}.
{3}, {T}: Draw a card. Activate only if you control a creature with power 4 or greater.

Forest

Jetmir's Garden

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

Lazotep Sliver

Sliver creatures you control have afflict 2. (Whenever a creature with afflict 2 becomes blocked, defending player loses 2 life.)
Whenever a nontoken Sliver you control dies, amass Slivers 2. (Put two +1/+1 counters on an Army you control. It's also a Sliver. If you don't control an Army, create a 0/0 black Sliver Army creature token first.)

Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Plains

Urza's Incubator

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

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.)

Sliver Legion

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

Spara's Headquarters

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

Scuttling Sliver

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

Moonmist

Transform all Humans. Prevent all combat damage that would be dealt this turn by creatures other than Werewolves and Wolves. (Only double-faced cards can be transformed.)

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Overgrown Tomb

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

Mountain

Cartographer's Survey

Look at the top seven cards of your library. Put up to two land cards from among them onto the battlefield tapped. Put the rest on the bottom of your library in a random order.

City of Brass

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

Ravager of the Fells

Trample
Whenever this creature transforms into Ravager of the Fells, it deals 2 damage to target opponent or planeswalker and 2 damage to up to one target creature that player or that planeswalker's controller controls.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Ravager of the Fells.

Huntmaster of the Fells

Whenever this creature enters or transforms into Huntmaster of the Fells, create a 2/2 green Wolf creature token and you gain 2 life.
At the beginning of each upkeep, if no spells were cast last turn, transform Huntmaster of the Fells.

Huntmaster of the Fells // Ravager of the Fells

Ulvenwald Abomination

Ulvenwald Captive

Defender
{T}: Add {G}.
{5}{G}{G}: Transform Ulvenwald Captive.

Ulvenwald Captive // Ulvenwald Abomination

Moonscarred Werewolf

Vigilance
{T}: Add {G}{G}.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Moonscarred Werewolf.

Scorned Villager

{T}: Add {G}.
At the beginning of each upkeep, if no spells were cast last turn, transform Scorned Villager.

Scorned Villager // Moonscarred Werewolf

Island

Raise the Palisade

Choose a creature type. Return all creatures that aren't of the chosen type to their owners' hands.

Hallowed Fountain

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

The World Tree

The World Tree enters tapped.
{T}: Add {G}.
As long as you control six or more lands, lands you control have "{T}: Add one mana of any color."
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice The World Tree: Search your library for any number of God cards, put them onto the battlefield, then shuffle.

Arcane Signet

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

Ketria Triome

({T}: Add {G}, {U}, or {R}.)
Ketria Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Arcane Adaptation

As Arcane Adaptation enters, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Hatchery Sliver

Replicate {1}{G} (When you cast this spell, copy it for each time you paid its replicate cost.)
Each Sliver spell you cast has replicate. The replicate cost is equal to its mana cost. (A copy of a permanent spell becomes a token.)

Raugrin Triome

({T}: Add {U}, {R}, or {W}.)
Raugrin Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Chromatic Lantern

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

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Bonescythe Sliver

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

Gemhide Sliver

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

Sacred Foundry

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

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.)

Stomping Ground

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

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Xenograft

As Xenograft enters, choose a creature type.
Each creature you control is the chosen type in addition to its other types.