Hour of Victory

Start your engines!
When this enchantment enters, create a 2/2 black Zombie creature token.
Max speed — {1}{B}, Sacrifice this enchantment: Search your library for a card, put it into your hand, then shuffle. Activate only as a sorcery.

Phelddagrif

{G}: Phelddagrif gains trample until end of turn. Target opponent creates a 1/1 green Hippo creature token.
{W}: Phelddagrif gains flying until end of turn. Target opponent gains 2 life.
{U}: Return Phelddagrif to its owner's hand. Target opponent may draw a card.

Pygmy Hippo

Whenever this creature attacks and isn't blocked, you may have defending player activate a mana ability of each land they control and lose all unspent mana. If you do, this creature assigns no combat damage this turn and at the beginning of your next main phase this turn, you add an amount of {C} equal to the amount of mana that player lost this way.

Adrenaline Jockey

Whenever a player casts a spell, if it's not their turn, this creature deals 4 damage to them.
Whenever you activate an exhaust ability, put a +1/+1 counter on this creature.

Avishkar Raceway

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
{T}: Add {C}.
Max speed — {3}, {T}, Discard a card: Draw a card.

Keruga, the Macrosage

Companion — Your starting deck contains only cards with mana value 3 or greater and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Keruga enters, draw a card for each other permanent you control with mana value 3 or greater.

Razor Hippogriff

Flying
When this creature enters, return target artifact card from your graveyard to your hand. You gain life equal to that card's mana value.

Kalakscion, Hunger Tyrant

Rampaging Hippo

Trample
Cycling {2} ({2}, Discard this card: Draw a card.)

Island

Tyr's Blessing

Target creature gains indestructible until end of turn. (Then exile this card. You may cast the creature later from exile.)

Blessed Hippogriff

Flying
Whenever this creature attacks, target attacking creature without flying gains flying until end of turn.

Blessed Hippogriff // Tyr's Blessing

Defiant Greatmaw

When this creature enters, put two -1/-1 counters on target creature you control.
Whenever you put one or more -1/-1 counters on this creature, remove a -1/-1 counter from another target creature you control.

Forest

Congregation Gryff

Flying, lifelink
Whenever this creature attacks while saddled, it gets +X/+X until end of turn, where X is the number of Mounts you control.
Saddle 3 (Tap any number of other creatures you control with total power 3 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Bull Hippo

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Momentum

Enchant creature
At the beginning of your upkeep, you may put a growth counter on this Aura.
Enchanted creature gets +1/+1 for each growth counter on this Aura.

Amonkhet Raceway

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
{T}: Add {C}.
Max speed — {T}: Target creature gains haste until end of turn.

Outpace Oblivion

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
When this enchantment enters, it deals 5 damage to up to one target creature or planeswalker.
{2}, Sacrifice this enchantment: It deals 2 damage to each player who doesn't have max speed.

Questing Phelddagrif

{G}: This creature gets +1/+1 until end of turn. Target opponent creates a 1/1 green Hippo creature token.
{W}: This creature gains protection from black and from red until end of turn. Target opponent gains 2 life.
{U}: This creature gains flying until end of turn. Target opponent may draw a card.

Plains

Yavimaya Hollow

{T}: Add {C}.
{G}, {T}: Regenerate target creature.

Breaching Hippocamp

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, untap another target creature you control.

Hydradoodle

As this creature enters, roll X six-sided dice. This creature enters with a number of +1/+1 counters on it equal to the total of those results.
Reach, trample

Feed

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Draw a card for each creature you control with power 3 or greater.