Eternal Thirst

Enchant creature
Enchanted creature has lifelink and "Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature." (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Grim Contest

Choose target creature you control and target creature an opponent controls. Each of those creatures deals damage equal to its toughness to the other.

Ambuscade

Target creature you control gets +1/+0 until end of turn. It deals damage equal to its power to target creature an opponent controls.

Wardscale Crocodile

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Crocanura

Reach (This creature can block creatures with flying.)
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Swamp

Icon of Ancestry

As Icon of Ancestry enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Lurking Crocodile

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Font of Return

{3}{B}, Sacrifice Font of Return: Return up to three target creature cards from your graveyard to your hand.

Grayscaled Gharial

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

Forest

Aspect of Gorgon

Enchant creature
Enchanted creature gets +1/+3 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy it.)

Cultural Exchange

Choose any number of creatures target player controls. Choose the same number of creatures another target player controls. Those players exchange control of those creatures. (This effect lasts indefinitely.)

Moldering Karok

Dukhara Scavenger

When Dukhara Scavenger enters, you may put target artifact or creature card from your graveyard on top of your library.

Hagra Crocodile

Hagra Crocodile can't block.
Landfall — Whenever a land you control enters, Hagra Crocodile gets +2/+2 until end of turn.

Treacherous Link

Enchant creature
All damage that would be dealt to enchanted creature is dealt to its controller instead.

Languish

All creatures get -4/-4 until end of turn.

Island

Akroma's Memorial

Creatures you control have flying, first strike, vigilance, trample, haste, and protection from black and from red.

Catacomb Crocodile

Scaled Behemoth

Guul Draz Mucklord

When Guul Draz Mucklord dies, put a +1/+1 counter on target creature you control.