Mabel, Heir to Cragflame

Other Mice you control get +1/+1.
When Mabel, Heir to Cragflame enters, create Cragflame, a legendary colorless Equipment artifact token with "Equipped creature gets +1/+1 and has vigilance, trample, and haste" and equip {2}.

Canyon Jerboa

Landfall — Whenever a land you control enters, creatures you control get +1/+1 until end of turn.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Venerable Warsinger

Vigilance, trample
Whenever Venerable Warsinger deals combat damage to a player, you may return target creature card with mana value X or less from your graveyard to the battlefield, where X is the amount of damage Venerable Warsinger dealt to that player.

Sacred Foundry

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

Hate Mirage

Choose up to two target creatures you don't control. For each of those creatures, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

Rugged Prairie

{T}: Add {C}.
{R/W}, {T}: Add {R}{R}, {R}{W}, or {W}{W}.

Crisis of Conscience

Choose one —
• Destroy all tokens.
• Destroy all nonland, nontoken permanents.

Universal Automaton

Changeling (This card is every creature type.)

Aspiring Champion

Menace
Ruinous Ascension — When Aspiring Champion deals combat damage to a player, sacrifice it. If you do, reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield, then shuffle the rest into your library. If that creature is a Demon, it deals damage equal to its power to each opponent.

Sol Ring

Sundown Pass

Sundown Pass enters tapped unless you control two or more other lands.
{T}: Add {R} or {W}.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Frontline Medic

Battalion — Whenever Frontline Medic and at least two other creatures attack, creatures you control gain indestructible until end of turn.
Sacrifice Frontline Medic: Counter target spell with {X} in its mana cost unless its controller pays {3}.

Armory Automaton

Whenever Armory Automaton enters or attacks, you may attach any number of target Equipment to it. (Control of the Equipment doesn't change.)

Plains

Blades of Velis Vel

Changeling (This card is every creature type.)
Up to two target creatures each get +2/+0 and gain all creature types until end of turn.

Razia's Purification

Each player chooses three permanents they control, then sacrifices the rest.

Risona, Asari Commander

Haste
Whenever Risona, Asari Commander deals combat damage to a player, if it doesn't have an indestructible counter on it, put an indestructible counter on it.
Whenever combat damage is dealt to you, remove an indestructible counter from Risona.

Avian Changeling

Changeling (This card is every creature type.)
Flying

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}.

Birthing Boughs

{4}, {T}: Create a 2/2 colorless Shapeshifter creature token with changeling. (It has every creature type.)

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Dark Apostle

Gift of Chaos — {3}, {T}: The next noncreature spell you cast this turn has cascade. (When you cast that 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.)

Raging Battle Mouse

The second spell you cast each turn costs {1} less to cast.
Celebration — At the beginning of combat on your turn, if two or more nonland permanents entered the battlefield under your control this turn, target creature you control gets +1/+1 until end of turn.

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.

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. Battlefield Forge deals 1 damage to you.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Hero's Blade

Equipped creature gets +3/+2.
Whenever a legendary creature you control enters, you may attach Hero's Blade to it.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Eerie Interlude

Exile any number of target creatures you control. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Changeling Sentinel

Changeling (This card is every creature type.)
Vigilance

Armory Mice

Celebration — Armory Mice gets +0/+2 as long as two or more nonland permanents entered the battlefield under your control this turn.

Maul of the Skyclaves

When Maul of the Skyclaves enters, attach it to target creature you control.
Equipped creature gets +2/+2 and has flying and first strike.
Equip {2}{W}{W}

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Changeling Berserker

Changeling (This card is every creature type.)
Haste
Champion a creature (When this enters, sacrifice it unless you exile another creature you control. When this leaves the battlefield, that card returns to the battlefield.)

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Changeling Hero

Changeling (This card is every creature type.)
Champion a creature (When this enters, sacrifice it unless you exile another creature you control. When this leaves the battlefield, that card returns to the battlefield.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Bloodthirster

Flying, trample
Whenever Bloodthirster deals combat damage to a player, untap it. After this phase, there is an additional combat phase.
Bloodthirster can't attack a player it has already attacked this turn.

Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Puresteel Paladin

Whenever an Equipment you control enters, you may draw a card.
Metalcraft — Equipment you control have equip {0} as long as you control three or more artifacts.

Anointed Procession

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Solemn Simulacrum

When Solemn Simulacrum enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When Solemn Simulacrum dies, you may draw a card.

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Jaxis, the Troublemaker

{R}, {T}, Discard a card: Create a token that's a copy of another target creature you control. It gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step. Activate only as a sorcery.
Blitz {1}{R} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Deathrender

Equipped creature gets +2/+2.
Whenever equipped creature dies, you may put a creature card from your hand onto the battlefield and attach Deathrender to it.
Equip {2}

Sacred Peaks

({T}: Add {R} or {W}.)
Sacred Peaks enters tapped.

Mondrak, Glory Dominus

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
{1}{W/P}{W/P}, Sacrifice two other artifacts and/or creatures: Put an indestructible counter on Mondrak, Glory Dominus. ({W/P} can be paid with either {W} or 2 life.)

Thespian's Stage

{T}: Add {C}.
{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

Crackle with Power

Crackle with Power deals five times X damage to each of up to X targets.

Flickerwisp

Flying
When Flickerwisp enters, exile another target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

War-Spike Changeling

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

Mirage Mirror

{2}: Mirage Mirror becomes a copy of target artifact, creature, enchantment, or land until end of turn.

Bladegraft Aspirant

Menace
Equipment spells you cast cost {1} less to cast.
Activated abilities of Equipment you control that target Bladegraft Aspirant cost {1} less to activate.

Three Blind Mice

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I — Create a 1/1 white Mouse creature token.
II, III — Create a token that's a copy of target token you control.
IV — Creatures you control get +1/+1 and gain vigilance until end of turn.

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

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.

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.)

Everybody Lives!

All creatures gain hexproof and indestructible until end of turn. Players gain hexproof until end of turn. Players can't lose life this turn and players can't lose the game or win the game this turn.

Coat of Arms

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

Enchanted Carriage

When Enchanted Carriage enters, create two 1/1 white Mouse creature tokens.
Crew 2 (Tap any number of creatures you control with total power 2 or more: This Vehicle becomes an artifact creature until end of turn.)

Restoration Angel

Flash
Flying
When Restoration Angel enters, you may exile target non-Angel creature you control, then return that card to the battlefield under your control.

Gnawing Crescendo

Creatures you control get +2/+0 until end of turn. Whenever a nontoken creature you control dies this turn, create a 1/1 black Rat creature token with "This creature can't block."

Arcane Signet

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

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.

Boros Guildgate

Boros Guildgate enters tapped.
{T}: Add {R} or {W}.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Taurean Mauler

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

Squeak By

Target creature you control gets +1/+1 until end of turn. It can't be blocked by creatures with power 3 or greater this turn.

Cheeky House-Mouse

Cheeky House-Mouse // Squeak By

Mountain

Impostor of the Sixth Pride

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Molten Echoes

As Molten Echoes enters, choose a creature type.
Whenever a nontoken creature you control of the chosen type enters, create a token that's a copy of that creature. That token gains haste. Exile it at the beginning of the next end step.

Inspiring Vantage

Inspiring Vantage enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {W}.

Alpine Meadow

({T}: Add {R} or {W}.)
Alpine Meadow enters tapped.

Spectator Seating

Spectator Seating enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Auriok Steelshaper

Equip costs you pay cost {1} less.
As long as Auriok Steelshaper is equipped, each creature you control that's a Soldier or a Knight gets +1/+1.

Flicker of Fate

Exile target creature or enchantment, then return it to the battlefield under its owner's control.