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.

Floodhound

{3}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Alpine Watchdog

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

Ainok Wayfarer

When this creature enters, mill three cards. You may put a land card from among them into your hand. If you don't, put a +1/+1 counter on this creature. (To mill three cards, put the top three cards of your library into your graveyard.)

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.

Ainok Bond-Kin

Outlast {1}{W} ({1}{W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has first strike.

Akroan Mastiff

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.

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.

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.

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.)

Fortress Kin-Guard

When this creature enters, it endures 1. (Put a +1/+1 counter on it or create a 1/1 white Spirit creature token.)

Snow Hound

{1}, {T}: Return this creature and target green or blue creature you control to their owner's hand.

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.

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.)

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.

Codecracker Hound

When this creature enters, look at the top two cards of your library. Put one into your hand and the other into your graveyard.
Warp {2}{U} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Faithful Watchdog

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

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.

Elven Warhounds

Whenever this creature becomes blocked by a creature, put that creature on top of its owner's library.

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

Rambunctious Mutt

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