Might of the Meek

Target creature gains trample until end of turn. It also gets +1/+0 until end of turn if you control a Mouse.
Draw a card.

Furycalm Snarl

As Furycalm Snarl enters, you may reveal a Mountain or Plains card from your hand. If you don't, Furycalm Snarl enters tapped.
{T}: Add {R} or {W}.

Seedglaive Mentor

Vigilance, haste
Valiant — Whenever Seedglaive Mentor becomes the target of a spell or ability you control for the first time each turn, put a +1/+1 counter on it.

Clifftop Retreat

Clifftop Retreat enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Boros Signet

Nettle Guard

Valiant — Whenever Nettle Guard becomes the target of a spell or ability you control for the first time each turn, it gets +0/+2 until end of turn.
{1}, Sacrifice Nettle Guard: Destroy target artifact or enchantment.

Dewdrop Cure

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, they draw a card before its other effects.)
Return up to two target creature cards each with mana value 2 or less from your graveyard to the battlefield. If the gift was promised, instead return up to three target creature cards each with mana value 2 or less from your graveyard to the battlefield.

Arcane Signet

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

Valley Rally

Gift a Food (You may promise an opponent a gift as you cast this spell. If you do, they create a Food token before its other effects. It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Creatures you control get +2/+0 until end of turn. If the gift was promised, target creature you control gains first strike until end of turn.

Exotic Orchard

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

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

Command Tower

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.

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.

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.

Slayers' Stronghold

{T}: Add {C}.
{R}{W}, {T}: Target creature gets +2/+0 and gains vigilance and haste until end of turn.

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.)

Rugged Prairie

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

Patchwork Banner

As Patchwork Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Roughshod Duo

Trample
Whenever you expend 4, target creature you control gets +1/+1 and gains trample until end of turn. (You expend 4 as you spend your fourth total mana to cast spells during a turn.)

Brave-Kin Duo

{1}, {T}: Target creature gets +1/+1 until end of turn. Activate only as a sorcery.

Spectator Seating

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

Boros Garrison

Boros Garrison enters tapped.
When Boros Garrison enters, return a land you control to its owner's hand.
{T}: Add {R}{W}.

Battlefield Forge

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

Talisman of Conviction

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

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.

Plains

Lupinflower Village

{T}: Add {C}.
{T}: Add {W}. Spend this mana only to cast a creature spell.
{1}{W}, {T}, Sacrifice Lupinflower Village: Look at the top six cards of your library. You may reveal a Bat, Bird, Mouse, or Rabbit card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Rockface Village

{T}: Add {C}.
{T}: Add {R}. Spend this mana only to cast a creature spell.
{R}, {T}: Target Lizard, Mouse, Otter, or Raccoon you control gets +1/+0 and gains haste until end of turn. Activate only as a sorcery.

Brambleguard Captain

At the beginning of combat on your turn, target creature you control gets +X/+0 until end of turn, where X is Brambleguard Captain's power.

Sol Ring

Mabel's Mettle

Target creature gets +2/+2 until end of turn. Up to one other target creature gets +1/+1 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.)

Temple of Triumph

Temple of Triumph enters tapped.
When Temple of Triumph enters, scry 1.
{T}: Add {R} or {W}.

Thistledown Players

Whenever Thistledown Players attacks, untap target nonland permanent.

Mountain

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}.