Mold Adder

Whenever an opponent casts a blue or black spell, you may put a +1/+1 counter on this creature.

Wilderness Elemental

Trample
Wilderness Elemental's power is equal to the number of nonbasic lands your opponents control.

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

Surrak Dragonclaw

Flash
This spell can't be countered.
Creature spells you control can't be countered.
Other creatures you control have trample.

Malignus

Malignus's power and toughness are each equal to half the highest life total among your opponents, rounded up.
Damage that would be dealt by Malignus can't be prevented.

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Dirtcowl Wurm

Whenever an opponent plays a land, put a +1/+1 counter on Dirtcowl Wurm.

Kavu Predator

Trample
Whenever an opponent gains life, put that many +1/+1 counters on Kavu Predator.

Coiling Woodworm

Coiling Woodworm's power is equal to the number of Forests on the battlefield.

Towering Titan

Towering Titan enters with X +1/+1 counters on it, where X is the total toughness of other creatures you control.
Sacrifice a creature with defender: All creatures gain trample until end of turn.

Dreamborn Muse

At the beginning of each player's upkeep, that player mills X cards, where X is the number of cards in their hand.

Thundering Mightmare

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Thundering Mightmare is paired with another creature, each of those creatures has "Whenever an opponent casts a spell, put a +1/+1 counter on this creature."

Undergrowth Scavenger

Undergrowth Scavenger enters with a number of +1/+1 counters on it equal to the number of creature cards in all graveyards.

Magnivore

Haste (This creature can attack and {T} as soon as it comes under your control.)
Magnivore's power and toughness are each equal to the number of sorcery cards in all graveyards.

Prime Speaker Zegana

Prime Speaker Zegana enters with X +1/+1 counters on it, where X is the greatest power among other creatures you control.
When Prime Speaker Zegana enters, draw cards equal to its power.

War Elemental

When War Elemental enters, sacrifice it unless an opponent was dealt damage this turn.
Whenever an opponent is dealt damage, put that many +1/+1 counters on War Elemental.

Skyshroud War Beast

Trample
As Skyshroud War Beast enters, choose an opponent.
Skyshroud War Beast's power and toughness are each equal to the number of nonbasic lands the chosen player controls.

Stag Beetle

Stag Beetle enters with X +1/+1 counters on it, where X is the number of other creatures on the battlefield.

Slag Fiend

Slag Fiend's power and toughness are each equal to the number of artifact cards in all graveyards.

Citanul Druid

Whenever an opponent casts an artifact spell, put a +1/+1 counter on Citanul Druid.

Academy Elite

Academy Elite enters with X +1/+1 counters on it, where X is the number of instant and sorcery cards in all graveyards.
{2}{U}, Remove a +1/+1 counter from Academy Elite: Draw a card, then discard a card.

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Realm Seekers

Realm Seekers enters with X +1/+1 counters on it, where X is the total number of cards in all players' hands.
{2}{G}, Remove a +1/+1 counter from Realm Seekers: Search your library for a land card, reveal it, put it into your hand, then shuffle.