Ashmouth Hound

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

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.)

Immolating Souleater

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

Watchdog

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

Scrapwork Mutt

When Scrapwork Mutt enters, you may discard a card. If you do, draw a card.
Unearth {1}{R} ({1}{R}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

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.

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.

Mad Dog

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

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.

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.

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.)

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."

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.)

Leashling

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

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.)

Lava Hounds

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

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.

Zodiac Dog

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

Karplusan Hound

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

Igneous Cur

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

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.

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.

Pyre Hound

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

Two-Headed Cerberus

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

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.

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.

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.

Lightning Hounds

Chandra's Magmutt

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

Fiery Hellhound

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

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Akoum Hellhound

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