Mistform Sliver

All Slivers have "{1}: This permanent becomes the creature type of your choice in addition to its other types until end of turn."

Ganax, Astral Hunter

Flying
Whenever Ganax, Astral Hunter or another Dragon you control enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Choose a Background (You can have a Background as a second commander.)

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Zurgo and Ojutai

Flying, haste
Zurgo and Ojutai has hexproof as long as it entered this turn.
Whenever one or more Dragons you control deal combat damage to a player or battle, look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. You may return one of those Dragons to its owner's hand.

Xenograft

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

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.

Metallic Sliver

Dragon Tempest

Whenever a creature you control with flying enters, it gains haste until end of turn.
Whenever a Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.

Quick Sliver

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

Mana Echoes

Whenever a creature enters, you may add an amount of {C} equal to the number of creatures you control that share a creature type with it.

Kolaghan, the Storm's Fury

Flying
Whenever a Dragon you control attacks, creatures you control get +1/+0 until end of turn.
Dash {3}{B}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

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.)

Utvara Hellkite

Flying
Whenever a Dragon you control attacks, create a 6/6 red Dragon creature token with flying.

Sylvia Brightspear

Partner with Khorvath Brightflame (When this creature enters, target player may put Khorvath into their hand from their library, then shuffle.)
Double strike
Dragons your team controls have double strike.

Harmonic Sliver

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

Silumgar, the Drifting Death

Flying, hexproof
Whenever a Dragon you control attacks, creatures defending player controls get -1/-1 until end of turn.

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.

Winged Sliver

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.)

Heart Sliver

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.)

Galerider Sliver

Sliver creatures you control have flying.

Two-Headed Sliver

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

Predatory Sliver

Regal Sliver

Sliver creatures you control have "When this creature enters, Slivers you control get +1/+1 until end of turn if you're the monarch. Otherwise, you become the monarch."

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.)

Striking Sliver

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

Lathliss, Dragon Queen

Flying
Whenever another nontoken Dragon you control enters, create a 5/5 red Dragon creature token with flying.
{1}{R}: Dragons you control get +1/+0 until end of turn.

Talon Sliver

Hibernation Sliver

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

Manaweft Sliver

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

Sliver Legion

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

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.

Biowaste Blob

Oozes you control get +1/+1.
At the beginning of your upkeep, if you control a commander, create a token that's a copy of Biowaste Blob.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Shifting Sliver

Slivers can't be blocked except by Slivers.

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.

Synapse Sliver

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

Plated Sliver

Capricious Sliver

Sliver creatures you control have "Whenever this creature deals combat damage to a player, exile the top card of your library. You may play that card this turn."

Brood Sliver

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

Miirym, Sentinel Wyrm

Flying, ward {2}
Whenever another nontoken Dragon you control enters, create a token that's a copy of it, except the token isn't legendary.

Scourge of Valkas

Flying
Whenever Scourge of Valkas or another Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.
{R}: Scourge of Valkas gets +1/+0 until end of turn.

Artificial Evolution

Change the text of target spell or permanent by replacing all instances of one creature type with another. The new creature type can't be Wall. (This effect lasts indefinitely.)

Crypt Sliver

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

Rooftop Storm

You may pay {0} rather than pay the mana cost for Zombie creature spells you cast.

Universal Automaton

Changeling (This card is every creature type.)

Descendants' Fury

Whenever one or more creatures you control deal combat damage to a player, you may sacrifice one of them. If you do, reveal cards from the top of your library until you reveal a creature card that shares a creature type with the sacrificed creature. Put that card onto the battlefield and the rest on the bottom of your library in a random order.

Sinew Sliver

Crystalline Sliver

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

Gemhide Sliver

All Slivers have "{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.)

Hivestone

Creatures you control are Slivers in addition to their other creature types.

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.)

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.