Contraband Livestock

Exile target creature, then roll a d20.
1—9 | Its controller creates a 4/4 green Ox creature token.
10—19 | Its controller creates a 2/2 green Boar creature token.
20 | Its controller creates a 0/1 white Goat creature token.

Giant Ox

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

Goldenhide Ox

Constellation — Whenever Goldenhide Ox or another enchantment enters the battlefield under your control, target creature must be blocked this turn if able.

Zodiac Ox

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Raging Bull

Makindi Ox

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

Earth-Origin Yak

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

Pillarfield Ox

Bovine Intervention

Destroy target artifact or creature. Its controller creates a 2/2 white Ox creature token.

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.)

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.

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.

Yoked Ox

Ironhoof Ox

Ironhoof Ox can't be blocked by more than one creature.

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.

Animal Sanctuary

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

Ox Drover

Vigilance
Ox Drover can't be blocked by Oxen.
Whenever Ox Drover enters the battlefield or attacks, target opponent creates a 2/4 white Ox creature token and you draw a card.

Wild Ox

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.