Pygmy Hippo

Whenever Pygmy Hippo 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, Pygmy Hippo 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.

Walking Sponge

{T}: Target creature loses your choice of flying, first strike, or trample until end of turn.

Aurochs Herd

Trample
When Aurochs Herd enters the battlefield, you may search your library for an Aurochs card, reveal it, put it into your hand, then shuffle.
Whenever Aurochs Herd attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

Zodiac Horse

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

Zodiac Rooster

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

Zodiac Ox

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

Giant Oyster

You may choose not to untap Giant Oyster during your untap step.
{T}: For as long as Giant Oyster remains tapped, target tapped creature doesn't untap during its controller's untap step, and at the beginning of each of your draw steps, put a -1/-1 counter on that creature. When Giant Oyster leaves the battlefield or becomes untapped, remove all -1/-1 counters from the creature.

Zodiac Rabbit

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

Aurochs

Trample
Whenever Aurochs attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

Bull Aurochs

Trample
Whenever Bull Aurochs attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

Zodiac Monkey

Volo, Guide to Monsters

Whenever you cast a creature spell that doesn't share a creature type with a creature you control or a creature card in your graveyard, copy that spell. (A copy of a creature spell becomes a token.)

Yavimaya Scion

Rimehorn Aurochs

Trample
Whenever Rimehorn Aurochs attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.
{2}{S}: Target creature blocks target creature this turn if able. ({S} can be paid with one mana from a snow source.)

Island Fish Jasconius

Island Fish Jasconius doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {U}{U}{U}. If you do, untap Island Fish Jasconius.
Island Fish Jasconius can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Island Fish Jasconius.

Brushwagg

Whenever Brushwagg blocks or becomes blocked, it gets -2/+2 until end of turn.

Bubbling Beebles

Bubbling Beebles can't be blocked as long as defending player controls an enchantment.