Don't Have

Deer-Dog

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

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.

Akoum Hellhound

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

Pack Leader

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

Have

Loyal Warhound

Vigilance
When this creature 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.

Angelo

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.)

Affa Guard Hound

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

Getting

Scythecat Cub

Trample
Landfall — Whenever a land you control enters, put a +1/+1 counter on target creature you control. If this is the second time this ability has resolved this turn, double the number of +1/+1 counters on that creature instead.

District Mascot

This creature enters with a +1/+1 counter on it.
{1}{G}, Remove two +1/+1 counters from this creature: Destroy target artifact.
Whenever this creature attacks while saddled, put a +1/+1 counter on it.
Saddle 1

Arbor Adherent

{T}: Add one mana of any color.
{T}: Add X mana of any one color, where X is the greatest toughness among other creatures you control.

Yoshimaru, Ever Faithful

Whenever another legendary permanent you control enters, put a +1/+1 counter on Yoshimaru.
Partner (You can have two commanders if both have partner.)

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Ashmouth Hound

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

Cathar's Companion

Whenever you cast a noncreature spell, this creature gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

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.

Jinnie Fay, Jetmir's Second

If you would create one or more tokens, you may instead create that many 2/2 green Cat creature tokens with haste or that many 3/1 green Dog creature tokens with vigilance.

Rin and Seri, Inseparable

Whenever you cast a Dog spell, create a 1/1 green Cat creature token.
Whenever you cast a Cat spell, create a 1/1 white Dog creature token.
{R}{G}{W}, {T}: Rin and Seri deals damage to any target equal to the number of Dogs you control. You gain life equal to the number of Cats you control.

Regal Caracal

Other Cats you control get +1/+1 and have lifelink. (Damage dealt by those creatures also causes you to gain that much life.)
When this creature enters, create two 1/1 white Cat creature tokens with lifelink.

Supply Runners

When this creature enters, put a +1/+1 counter on each other creature you control.

Rinoa Heartilly

When Rinoa Heartilly enters, create Angelo, a legendary 1/1 green and white Dog creature token.
Angelo Cannon — Whenever Rinoa Heartilly attacks, another target creature you control gets +1/+1 until end of turn for each creature you control.

Alpine Watchdog

Vigilance (Attacking doesn't cause this creature to tap.)

Pako, Arcane Retriever

Partner with Haldan, Avid Arcanist
Haste
Whenever Pako attacks, exile the top card of each player's library and put a fetch counter on each of them. Put a +1/+1 counter on Pako for each noncreature card exiled this way.

Release the Dogs

Create four 1/1 white Dog creature tokens.

Generous Pup

Vigilance
Whenever one or more +1/+1 counters are put on this creature, put a +1/+1 counter on each other creature you control. This ability triggers only once each turn.

Faithful Watchdog

Vigilance
This creature enters with three +1/+1 counters on it.