Two-Headed Cerberus

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

Akoum Hellhound

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

Underworld Rage-Hound

This creature 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.)
This creature escapes with a +1/+1 counter on it.

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.)
This creature attacks each combat if able.
Enchanted creature gets +2/+2 and attacks each combat if able.

Goldhound

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

Chandra's Magmutt

{T}: This creature deals 1 damage to target player or planeswalker.

Igneous Cur

{1}{R}: This creature gets +2/+0 until end of turn.

Scrapyard Mongrel

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

Fiery Hellhound

{R}: This creature gets +1/+0 until end of turn.

Scrapwork Mutt

When this creature 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.)

Edgewall Pack

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

Immolating Souleater

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

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 attacks, add {R} for each attacking creature.

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 this creature becomes monstrous, it deals 2 damage to each opponent and each creature they control.

Pyre Hound

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

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 this creature.

Bolt Hound

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

Ashmouth Hound

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

Hellfire Mongrel

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