Hapatra, Vizier of Poisons

Whenever Hapatra deals combat damage to a player, you may put a -1/-1 counter on target creature.
Whenever you put one or more -1/-1 counters on a creature, create a 1/1 green Snake creature token with deathtouch.

Swamp

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.

Foul Orchard

This land enters tapped.
{T}: Add {B} or {G}.

Supernatural Stamina

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Nest of Scarabs

Whenever you put one or more -1/-1 counters on a creature, create that many 1/1 black Insect creature tokens.

Obelisk Spider

Reach
Whenever this creature deals combat damage to a creature, put a -1/-1 counter on that creature.
Whenever you put one or more -1/-1 counters on a creature, each opponent loses 1 life and you gain 1 life.

Baleful Ammit

Lifelink
When this creature enters, put a -1/-1 counter on target creature you control.

Festering Mummy

When this creature dies, you may put a -1/-1 counter on target creature.

Cartouche of Strength

Enchant creature you control
When this Aura enters, you may have enchanted creature fight target creature an opponent controls. (Each deals damage equal to its power to the other.)
Enchanted creature gets +1/+1 and has trample.

Trial of Ambition

When this enchantment enters, target opponent sacrifices a creature of their choice.
When a Cartouche you control enters, return this enchantment to its owner's hand.

Cartouche of Ambition

Enchant creature you control
When this Aura enters, you may put a -1/-1 counter on target creature.
Enchanted creature gets +1/+1 and has lifelink.

Crocodile of the Crossing

Haste
When this creature enters, put a -1/-1 counter on target creature you control.

Shed Weakness

Target creature gets +2/+2 until end of turn. You may remove a -1/-1 counter from it.

Oashra Cultivator

{2}{G}, {T}, Sacrifice this creature: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Forest

Liliana, Death Wielder

+2: Put a -1/-1 counter on up to one target creature.
−3: Destroy target creature with a -1/-1 counter on it.
−10: Return all creature cards from your graveyard to the battlefield.

Kessig Recluse

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Channeler Initiate

When this creature enters, put three -1/-1 counters on target creature you control.
{T}, Remove a -1/-1 counter from this creature: Add one mana of any color.

Ammit Eternal

Afflict 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
Whenever an opponent casts a spell, put a -1/-1 counter on this creature.
Whenever this creature deals combat damage to a player, remove all -1/-1 counters from it.

Jungle Hollow

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {G}.

Liliana's Influence

Put a -1/-1 counter on each creature you don't control. You may search your library and/or graveyard for a card named Liliana, Death Wielder, reveal it, and put it into your hand. If you search your library this way, shuffle.

Decimator Beetle

When this creature enters, put a -1/-1 counter on target creature you control.
Whenever this creature attacks, remove a -1/-1 counter from target creature you control and put a -1/-1 counter on up to one target creature defending player controls.