Warclamp Mastiff

First strike (This creature deals combat damage before creatures without first strike.)

Spirited Companion

When Spirited Companion enters, draw a card.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

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.

Plains

Bolt Hound

Haste (This creature can attack and {T} as soon as it comes under your control.)
Whenever Bolt Hound attacks, other creatures you control get +1/+0 until end of turn.

Rally the Ranks

As Rally the Ranks enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.

Lightning Helix

Lightning Helix deals 3 damage to any target and you gain 3 life.

Loyal Warhound

Vigilance
When Loyal Warhound enters, if an opponent controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Summary Judgment

Summary Judgment deals 3 damage to target tapped creature.
Addendum — If you cast this spell during your main phase, it deals 5 damage instead.

Mutavault

{T}: Add {C}.
{1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Isamaru, Hound of Konda

Brave the Elements

Choose a color. White creatures you control gain protection from the chosen color until end of turn.

Selfless Savior

Sacrifice Selfless Savior: Another target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Pack Leader

Other Dogs you control get +1/+1.
Whenever Pack Leader attacks, prevent all combat damage that would be dealt this turn to Dogs you control.

Alpine Meadow

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

Battlefield Forge

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

Morning Apparition

Flying, vigilance
If Morning Apparition would be put into a graveyard from anywhere, exile it instead.

Mourning Patrol

Vigilance
Disturb {3}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Mourning Patrol // Morning Apparition

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Mountain

Affa Guard Hound

Flash (You may cast this spell any time you could cast an instant.)
When Affa Guard Hound enters, target creature gets +0/+3 until end of turn.