Harmonic Sliver

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

Harabaz Druid

{T}: Add X mana of any one color, where X is the number of Allies you control.

Rebuff the Wicked

Counter target spell that targets a permanent you control.

Turtleshell Changeling

Changeling (This card is every creature type.)
{1}{U}: Switch Turtleshell Changeling's power and toughness until end of turn.

Chameleon Colossus

Changeling (This card is every creature type.)
Protection from black
{2}{G}{G}: Chameleon Colossus gets +X/+X until end of turn, where X is its power.

Valiant Changeling

This spell costs {1} less to cast for each creature type among creatures you control. This effect can't reduce the amount of mana this spell costs by more than {5}.
Changeling (This card is every creature type.)
Double strike

Savai Triome

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

Counterspell

Unsettled Mariner

Changeling (This card is every creature type.)
Whenever you or a permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.

Sage's Dousing

Counter target spell unless its controller pays {3}. If you control a Wizard, draw a card.

Wanderwine Hub

As Wanderwine Hub enters, you may reveal a Merfolk card from your hand. If you don't, Wanderwine Hub enters tapped.
{T}: Add {W} or {U}.

Moritte of the Frost

Changeling (This card is every creature type.)
You may have Moritte of the Frost enter as a copy of a permanent you control, except it's legendary and snow in addition to its other types and, if it's a creature, it enters with two additional +1/+1 counters on it and has changeling.

Arcane Signet

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

Universal Automaton

Changeling (This card is every creature type.)

Ancient Amphitheater

As Ancient Amphitheater enters, you may reveal a Giant card from your hand. If you don't, Ancient Amphitheater enters tapped.
{T}: Add {R} or {W}.

Deadly Alliance

This spell costs {1} less to cast for each creature in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)
Destroy target creature or planeswalker.

Priest of Titania

{T}: Add {G} for each Elf on the battlefield.

Krosan Warchief

Beast spells you cast cost {1} less to cast.
{1}{G}: Regenerate target Beast.

Secluded Glen

As Secluded Glen enters, you may reveal a Faerie card from your hand. If you don't, Secluded Glen enters tapped.
{T}: Add {U} or {B}.

Shapesharer

Changeling (This card is every creature type.)
{2}{U}: Target Shapeshifter becomes a copy of target creature until your next turn.

Thunderherd Migration

As an additional cost to cast this spell, reveal a Dinosaur card from your hand or pay {1}.
Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

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.

Firja's Retribution

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 4/4 white Angel Warrior creature token with flying and vigilance.
II — Until end of turn, Angels you control gain "{T}: Destroy target creature with power less than this creature's power."
III — Angels you control gain double strike until end of turn.

Ketria Triome

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

Gilt-Leaf Archdruid

Whenever you cast a Druid spell, you may draw a card.
Tap seven untapped Druids you control: Gain control of all lands target player controls.

War-Spike Changeling

Changeling (This card is every creature type.)
{R}: War-Spike Changeling gains first strike until end of turn.

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

Avian Changeling

Changeling (This card is every creature type.)
Flying

Graveshifter

Changeling (This card is every creature type.)
When Graveshifter enters, you may return target creature card from your graveyard to your hand.

Raugrin Triome

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

Changeling Sentinel

Changeling (This card is every creature type.)
Vigilance

Orvar, the All-Form

Changeling
Whenever you cast an instant or sorcery spell, if it targets one or more other permanents you control, create a token that's a copy of one of those permanents.
When a spell or ability an opponent controls causes you to discard this card, create a token that's a copy of target permanent.

Contested Cliffs

{T}: Add {C}.
{R}{G}, {T}: Target Beast creature you control fights target creature an opponent controls. (Each deals damage equal to its power to the other.)

Impostor of the Sixth Pride

Murmuring Bosk

({T}: Add {G}.)
As Murmuring Bosk enters, you may reveal a Treefolk card from your hand. If you don't, Murmuring Bosk enters tapped.
{T}: Add {W} or {B}. Murmuring Bosk deals 1 damage to you.

Rin and Seri, Inseparable

Whenever you cast a Dog spell, create a 1/1 green Cat creature token.
Whenever you cast a Cat spell, create a 1/1 white Dog creature token.
{R}{G}{W}, {T}: Rin and Seri, Inseparable deals damage to any target equal to the number of Dogs you control. You gain life equal to the number of Cats you control.

Joraga Treespeaker

Level up {1}{G} ({1}{G}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-4
1/2
{T}: Add {G}{G}.
LEVEL 5+
1/4
Elves you control have "{T}: Add {G}{G}."

The Bears of Littjara

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 2/2 blue Shapeshifter creature token with changeling.
II — Any number of target Shapeshifter creatures you control have base power and toughness 4/4.
III — Choose up to one target creature or planeswalker. Each creature with power 4 or greater you control deals damage equal to its power to that permanent.

Zagoth Triome

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

Crystalline Sliver

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

Peer Pressure

Choose a creature type. If you control more creatures of that type than each other player, you gain control of all creatures of that type. (This effect lasts indefinitely.)

Skeletal Changeling

Changeling (This card is every creature type.)
{1}{B}: Regenerate Skeletal Changeling.

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.

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.)

Goblin Warchief

Goblin spells you cast cost {1} less to cast.
Goblins you control have haste.

Coveted Prize

This spell costs {1} less to cast for each creature in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)
Search your library for a card, put it into your hand, then shuffle. If you have a full party, you may cast a spell with mana value 4 or less from your hand without paying its mana cost.

Irregular Cohort

Changeling (This card is every creature type.)
When Irregular Cohort enters, create a 2/2 colorless Shapeshifter creature token with changeling.

Lord of the Unreal

Illusion creatures you control get +1/+1 and have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Guardian Gladewalker

Changeling (This card is every creature type.)
When Guardian Gladewalker enters, put a +1/+1 counter on target creature.

Rattlechains

Flash
Flying
When Rattlechains enters, target Spirit gains hexproof until end of turn.
You may cast Spirit spells as though they had flash.

Mistwalker

Changeling (This card is every creature type.)
Flying
{1}{U}: Mistwalker gets +1/-1 until end of turn.

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

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.

Sol Ring

Auntie's Hovel

As Auntie's Hovel enters, you may reveal a Goblin card from your hand. If you don't, Auntie's Hovel enters tapped.
{T}: Add {B} or {R}.

Moonglove Changeling

Changeling (This card is every creature type.)
{B}: Moonglove Changeling gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy that creature.)

Fist of Suns

You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast.

Island

Spellstutter Sprite

Flash
Flying
When Spellstutter Sprite enters, counter target spell with mana value X or less, where X is the number of Faeries you control.

Shields of Velis Vel

Changeling (This card is every creature type.)
Creatures target player controls get +0/+1 and gain all creature types until end of turn.

Swarmyard

{T}: Add {C}.
{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Galecaster Colossus

Tap an untapped Wizard you control: Return target nonland permanent you don't control to its owner's hand.

Forest

Wirewood Lodge

{T}: Add {C}.
{G}, {T}: Untap target Elf.

Knight Exemplar

First strike (This creature deals combat damage before creatures without first strike.)
Other Knight creatures you control get +1/+1 and have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Patron Wizard

Tap an untapped Wizard you control: Counter target spell unless its controller pays {1}.

Volatile Claws

Until end of turn, creatures you control get +2/+0 and gain all creature types.

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.

Primal Beyond

As Primal Beyond enters, you may reveal an Elemental card from your hand. If you don't, Primal Beyond enters tapped.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast an Elemental spell or activate an ability of an Elemental.

Mountain

Mothdust Changeling

Changeling (This card is every creature type.)
Tap an untapped creature you control: Mothdust Changeling gains flying until end of turn.

Plains

Wort, Boggart Auntie

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
At the beginning of your upkeep, you may return target Goblin card from your graveyard to your hand.

Wizard's Retort

This spell costs {1} less to cast if you control a Wizard.
Counter target spell.

Indatha Triome

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

Woodland Changeling

Ally Encampment

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast an Ally spell.
{1}, {T}, Sacrifice Ally Encampment: Return target Ally you control to its owner's hand.

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on Bloodline Pretender.

Dragon's Hoard

Whenever a Dragon you control enters, put a gold counter on Dragon's Hoard.
{T}, Remove a gold counter from Dragon's Hoard: Draw a card.
{T}: Add one mana of any color.

Venomous Changeling

Changeling (This card is every creature type.)
Deathtouch

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.

Cast Off

Destroy all non-Giant creatures. (Then exile this card. You may cast the creature later from exile.)

Realm-Cloaked Giant

Realm-Cloaked Giant // Cast Off

Mark of the Oni

Enchant creature
You control enchanted creature.
At the beginning of the end step, if you control no Demons, sacrifice Mark of the Oni.

Fire-Belly Changeling

Changeling (This card is every creature type.)
{R}: Fire-Belly Changeling gets +1/+0 until end of turn. Activate no more than twice each turn.

Gladewalker Ritualist

Changeling (This card is every creature type.)
Whenever another creature you control named Gladewalker Ritualist enters, draw a card.

Zareth San, the Trickster

Flash
{2}{U}{B}, Return an unblocked attacking Rogue you control to its owner's hand: Put Zareth San, the Trickster from your hand onto the battlefield tapped and attacking.
Whenever Zareth San deals combat damage to a player, you may put target permanent card from that player's graveyard onto the battlefield under your control.