Holy Cow

Flash
Flying
When Holy Cow enters the battlefield, you gain 2 life and scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Purphoros's Emissary

Bestow {6}{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.)
Menace (This creature can't be blocked except by two or more creatures.)
Enchanted creature gets +3/+3 and has menace.

Impostor of the Sixth Pride

Changeling (This card is every creature type.)

Makindi Ox

Landfall — Whenever a land enters the battlefield under your control, tap target creature an opponent controls.

Giant Ox

Giant Ox crews Vehicles using its toughness rather than its power.

Liberated Livestock

When Liberated Livestock dies, create a 1/1 white Cat creature token with lifelink, a 1/1 white Bird creature token with flying, and a 2/4 white Ox creature token. For each of those tokens, you may put an Aura card from your hand and/or graveyard onto the battlefield attached to it.

Earth-Origin Yak

When Earth-Origin Yak enters the battlefield, creatures you control get +1/+1 until end of turn.

Valiant Changeling

This spell costs {1} less to cast for each creature type among creatures you control. This effect can't reduce the amount of mana this spell costs by more than {5}.
Changeling (This card is every creature type.)
Double strike

Changeling Berserker

Changeling (This card is every creature type.)
Haste
Champion a creature (When this enters the battlefield, sacrifice it unless you exile another creature you control. When this leaves the battlefield, that card returns to the battlefield.)

War-Spike Changeling

Changeling (This card is every creature type.)
{R}: War-Spike Changeling gains first strike until end of turn.

Irregular Cohort

Changeling (This card is every creature type.)
When Irregular Cohort enters the battlefield, create a 2/2 colorless Shapeshifter creature token with changeling.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Fire-Belly Changeling

Changeling (This card is every creature type.)
{R}: Fire-Belly Changeling gets +1/+0 until end of turn. Activate no more than twice each turn.

Bartered Cow

When Bartered Cow dies or when you discard it, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Charging Cinderhorn

Haste
At the beginning of each player's end step, if no creatures attacked this turn, put a fury counter on Charging Cinderhorn. Then Charging Cinderhorn deals damage equal to the number of fury counters on it to that player.

Ox of Agonas

When Ox of Agonas enters the battlefield, discard your hand, then draw three cards.
Escape—{R}{R}, Exile eight other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)
Ox of Agonas escapes with a +1/+1 counter on it.

Changeling Hero

Changeling (This card is every creature type.)
Champion a creature (When this enters the battlefield, sacrifice it unless you exile another creature you control. When this leaves the battlefield, that card returns to the battlefield.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Arc Runner

Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice Arc Runner.

Inquisitor's Ox

Delirium — Inquisitor's Ox gets +1/+0 and has vigilance as long as there are four or more card types among cards in your graveyard.

Changeling Sentinel

Changeling (This card is every creature type.)
Vigilance

Yoked Ox

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters the battlefield, choose a creature type.
Whenever another creature of the chosen type enters the battlefield under your control, put a +1/+1 counter on Bloodline Pretender.

Pillarfield Ox

Bruse Tarl, Roving Rancher

Oxen you control have double strike.
Whenever Bruse Tarl, Roving Rancher enters the battlefield or attacks, exile the top card of your library. If it's a land card, create a 2/2 white Ox creature token. Otherwise, you may cast it until the end of your next turn.

Avian Changeling

Changeling (This card is every creature type.)
Flying

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on Taurean Mauler.