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.

War Squeak

Enchant creature
When War Squeak enters, target creature an opponent controls can't block this turn.
Enchanted creature gets +1/+1 and has haste.

Flowerfoot Swordmaster

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Valiant — Whenever this creature becomes the target of a spell or ability you control for the first time each turn, Mice you control get +1/+0 until end of turn.

Banishing Light

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.

Mouse Trapper

Flash
Valiant — Whenever Mouse Trapper becomes the target of a spell or ability you control for the first time each turn, tap target creature an opponent controls.

Salvation Swan

Flash
Flying
Whenever Salvation Swan or another Bird you control enters, exile up to one target creature you control without flying. Return it to the battlefield under its owner's control with a flying counter on it at the beginning of the next end step.

Frilled Sparkshooter

Menace, reach
Frilled Sparkshooter enters with a +1/+1 counter on it if an opponent lost life this turn.

Mountain

Wax-Wane Witness

Flying, vigilance
Whenever you gain or lose life during your turn, Wax-Wane Witness gets +1/+0 until end of turn.

Veteran Guardmouse

Valiant — Whenever Veteran Guardmouse becomes the target of a spell or ability you control for the first time each turn, it gets +1/+0 and gains first strike until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Playful Shove

Playful Shove deals 1 damage to any target.
Draw a card.

Agate Assault

Choose one —
• Agate Assault deals 4 damage to target creature. If that creature would die this turn, exile it instead.
• Exile target artifact.

Whiskerquill Scribe

Valiant — Whenever Whiskerquill Scribe becomes the target of a spell or ability you control for the first time each turn, you may discard a card. If you do, draw a card.

Thistledown Players

Whenever Thistledown Players attacks, untap target nonland permanent.

Warren Elder

{3}{W}: Creatures you control get +1/+1 until end of turn.

Driftgloom Coyote

When Driftgloom Coyote enters, exile target creature an opponent controls until Driftgloom Coyote leaves the battlefield. If that creature had power 2 or less, put a +1/+1 counter on Driftgloom Coyote.

Hearthborn Battler

Haste
Whenever a player casts their second spell each turn, Hearthborn Battler deals 2 damage to target opponent.

Brightblade Stoat

Plains

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}.

Three Tree Mascot

Changeling (This card is every creature type.)
{1}: Add one mana of any color. Activate only once each turn.

Shrike Force

Rabbit Response

Creatures you control get +2/+1 until end of turn. If you control a Rabbit, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Intrepid Rabbit

Offspring {1} (You may pay an additional {1} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
When this creature enters, target creature you control gets +1/+1 until end of turn.

Sonar Strike

Sonar Strike deals 4 damage to target attacking, blocking, or tapped creature. You gain 3 life if you control a Bat.