Zodiac Dog

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)

Leashling

Put a card from your hand on top of your library: Return Leashling to its owner's hand.

Monstrous Hound

Monstrous Hound can't attack unless you control more lands than defending player.
Monstrous Hound can't block unless you control more lands than attacking player.

Pyre Hound

Trample
Whenever you cast an instant or sorcery spell, put a +1/+1 counter on Pyre Hound.

Hellfire Mongrel

At the beginning of each opponent's upkeep, if that player has two or fewer cards in hand, Hellfire Mongrel deals 2 damage to that player.

Blood Hound

Whenever you're dealt damage, you may put that many +1/+1 counters on Blood Hound.
At the beginning of your end step, remove all +1/+1 counters from Blood Hound.

Komainu Battle Armor

Menace
Equipped creature gets +2/+2 and has menace.
Whenever Komainu Battle Armor or equipped creature deals combat damage to a player, goad each creature that player controls.
Reconfigure {4} ({4}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Iron Mastiff

Whenever Iron Mastiff attacks, roll a d20 for each player being attacked and ignore all but the highest roll.
1—9 | Iron Mastiff deals damage equal to its power to you.
10—19 | Iron Mastiff deals damage equal to its power to defending player.
20 | Iron Mastiff deals damage equal to its power to each opponent.

Igneous Cur

{1}{R}: Igneous Cur gets +2/+0 until end of turn.

Sterling Hound

When Sterling Hound enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Immolating Souleater

{R/P}: Immolating Souleater gets +1/+0 until end of turn. ({R/P} can be paid with either {R} or 2 life.)

Arcbound Tracker

Menace
Modular 2 (This creature enters with two +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)
Whenever you cast a spell other than your first spell each turn, put a +1/+1 counter on Arcbound Tracker.

Pack Mastiff

{1}{R}: Each creature you control named Pack Mastiff gets +1/+0 until end of turn.

Scrapyard Mongrel

As long as you control an artifact, Scrapyard Mongrel gets +2/+0 and has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Hound of Griselbrand

Double strike
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Karplusan Hound

Whenever Karplusan Hound attacks, if you control a Chandra planeswalker, this creature deals 2 damage to any target.

Enduring Courage

Whenever another creature you control enters, it gets +2/+0 and gains haste until end of turn.
When Enduring Courage dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Mountain

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Mad Dog

At the beginning of your end step, if Mad Dog didn't attack or come under your control this turn, sacrifice it.

Lava Hounds

Haste
When Lava Hounds enters, it deals 4 damage to you.

Watchdog

Watchdog blocks each combat if able.
As long as Watchdog is untapped, all creatures attacking you get -1/-0.

Ainok Tracker

First strike
Morph {4}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Slumbering Cerberus

This creature doesn't untap during your untap step.
Morbid — At the beginning of each end step, if a creature died this turn, untap this creature.

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.

Akoum Hellhound

Landfall — Whenever a land you control enters, Akoum Hellhound gets +2/+2 until end of turn.

Mogis's Warhound

Bestow {2}{R} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Mogis's Warhound attacks each combat if able.
Enchanted creature gets +2/+2 and attacks each combat if able.

Tesak, Judith's Hellhound

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)
Other Dogs you control have unleash.
Creatures you control with counters on them have haste.
Whenever Tesak, Judith's Hellhound attacks, add {R} for each attacking creature.

Edgewall Pack

Menace (This creature can't be blocked except by two or more creatures.)
When Edgewall Pack enters, create a 1/1 black Rat creature token with "This creature can't block."

Fiery Hellhound

{R}: Fiery Hellhound gets +1/+0 until end of turn.

Corpse Cur

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Corpse Cur enters, you may return target creature card with infect from your graveyard to your hand.

Ashmouth Hound

Whenever Ashmouth Hound blocks or becomes blocked by a creature, Ashmouth Hound deals 1 damage to that creature.

Goldhound

First strike
Menace (This creature can't be blocked except by two or more creatures.)
{T}, Sacrifice Goldhound: Add one mana of any color.

Underworld Rage-Hound

Underworld Rage-Hound attacks each combat if able.
Escape—{3}{R}, Exile three other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)
Underworld Rage-Hound escapes with a +1/+1 counter on it.

Two-Headed Cerberus

Double strike (This creature deals both first-strike and regular combat damage.)

Chandra's Magmutt

{T}: Chandra's Magmutt deals 1 damage to target player or planeswalker.

Wildfire Cerberus

{5}{R}{R}: Monstrosity 1. (If this creature isn't monstrous, put a +1/+1 counter on it and it becomes monstrous.)
When Wildfire Cerberus becomes monstrous, it deals 2 damage to each opponent and each creature they control.