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

Phelia, Exuberant Shepherd

Flash
Whenever Phelia attacks, exile up to one other target nonland permanent. At the beginning of the next end step, return that card to the battlefield under its owner's control. If it entered under your control, put a +1/+1 counter on Phelia.

Blink Dog

Double strike
Teleport — {3}{W}: This creature phases out. (Treat it and anything attached to it as though they don't exist until your next turn.)

Alpine Watchdog

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

Thrasios, Triton Hero

{4}: Scry 1, then reveal the top card of your library. If it's a land card, put it onto the battlefield tapped. Otherwise, draw a card.
Partner (You can have two commanders if both have partner.)

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.

Sophia, Dogged Detective

When Sophia enters, create Tiny, a legendary 2/2 green Dog Detective creature token with trample.
{1}, Sacrifice an artifact token: Put a +1/+1 counter on each Dog you control.
Whenever a Dog you control deals combat damage to a player, create a Food token, then investigate.

Wild Mongrel

Discard a card: This creature gets +1/+1 and becomes the color of your choice until end of turn.

Mischievous Pup

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, return up to one other target permanent you control to its owner's hand.

Mordenkainen

+2: Draw two cards, then put a card from your hand on the bottom of your library.
−2: Create a blue Dog Illusion creature token with "This token's power and toughness are each equal to twice the number of cards in your hand."
−10: Exchange your hand and library, then shuffle. You get an emblem with "You have no maximum hand size."

Rambunctious Mutt

When this creature enters, destroy target artifact or enchantment an opponent controls.

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.)

Faithful Watchdog

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

Tireless Tracker

Landfall — Whenever a land you control enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on this creature.

Animal Sanctuary

{T}: Add {C}.
{2}, {T}: Put a +1/+1 counter on target Bird, Cat, Dog, Goat, Ox, or Snake.

Release the Dogs

Create four 1/1 white Dog creature tokens.

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.

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.

Ainok Strike Leader

Whenever you attack with this creature and/or your commander, for each opponent, create a 1/1 red Goblin creature token that's tapped and attacking that player.
Sacrifice this creature: Creature tokens you control gain indestructible until end of turn.

Chrome Companion

Whenever this creature becomes tapped, you gain 1 life.
{2}, {T}: Put target card from a graveyard on the bottom of its owner's library.

Realmwalker

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Spirited Companion

Selfless Savior

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

Isamaru, Hound of Konda

Mowu, Loyal Companion

Vigilance, trample
If one or more +1/+1 counters would be put on Mowu, that many plus one +1/+1 counters are put on it instead.

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.

Spider-Ham, Peter Porker

When Spider-Ham enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Animal May-Ham — Other Spiders, Boars, Bats, Bears, Birds, Cats, Dogs, Frogs, Jackals, Lizards, Mice, Otters, Rabbits, Raccoons, Rats, Squirrels, Turtles, and Wolves you control get +1/+1.

Torgal, A Fine Hound

Whenever you cast your first Human creature spell each turn, that creature enters with an additional +1/+1 counter on it for each Dog and/or Wolf you control.
{T}: Add one mana of any color.

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.

K-9, Mark I

Negative — As long as K-9 is untapped, other legendary creatures you control have ward {1}.
Affirmative — {1}{U}, {T}: Target legendary creature can't be blocked this turn.
Doctor's companion (You can have two commanders if the other is the Doctor.)