Putrid Imp

Discard a card: Putrid Imp gains flying until end of turn.
Threshold — As long as seven or more cards are in your graveyard, Putrid Imp gets +1/+1 and can’t block.

Petravark

When Petravark enters the battlefield, exile target land.
When Petravark leaves the battlefield, return the exiled card to the battlefield under its owner’s control.

Dreamwinder

Dreamwinder can’t attack unless defending player controls an Island.
, Sacrifice an Island: Target land becomes an Island until end of turn.

Phantom Whelp

When Phantom Whelp attacks or blocks, return it to its owner’s hand at end of combat. (Return it only if it’s on the battlefield.)

Earth Rift

Destroy target land.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Stone-Tongue Basilisk

Whenever Stone-Tongue Basilisk deals combat damage to a creature, destroy that creature at end of combat.
Threshold — As long as seven or more cards are in your graveyard, all creatures able to block Stone-Tongue Basilisk do so.

Chamber of Manipulation

Enchant land
Enchanted land has “, Discard a card: Gain control of target creature until end of turn.”

Ember Beast

Ember Beast can’t attack or block alone.

Deluge

Tap all creatures without flying.

Balshan Griffin

Flying
, Discard a card: Return Balshan Griffin to its owner’s hand.

Aven Shrine

Whenever a player casts a spell, that player gains X life, where X is the number of cards in all graveyards with the same name as that spell.

Cephalid Shrine

Whenever a player casts a spell, counter that spell unless that player pays , where X is the number of cards in all graveyards with the same name as the spell.

Stone-Tongue Basilisk

Whenever Stone-Tongue Basilisk deals combat damage to a creature, destroy that creature at end of combat.
Threshold — As long as seven or more cards are in your graveyard, all creatures able to block Stone-Tongue Basilisk do so.

Goblin Trenches

, Sacrifice a land: Create two 1/1 red and white Goblin Soldier creature tokens.

Enlistment Officer

First strike
When Enlistment Officer enters the battlefield, reveal the top four cards of your library. Put all Soldier cards revealed this way into your hand and the rest on the bottom of your library in any order.

Kavu Howler

When Kavu Howler enters the battlefield, reveal the top four cards of your library. Put all Kavu cards revealed this way into your hand and the rest on the bottom of your library in any order.

Tidal Courier

When Tidal Courier enters the battlefield, reveal the top four cards of your library. Put all Merfolk cards revealed this way into your hand and the rest on the bottom of your library in any order.
: Tidal Courier gains flying until end of turn.

Fervor

Creatures you control have haste. (They can attack and as soon as they come under your control.)

Aether Flash

Whenever a creature enters the battlefield, Aether Flash deals 2 damage to it.

Amphibious Kavu

Whenever Amphibious Kavu blocks or becomes blocked by one or more blue and/or black creatures, Amphibious Kavu gets +3/+3 until end of turn.

Hunting Drake

Flying
When Hunting Drake enters the battlefield, put target red or green creature on top of its owner’s library.

Mire Kavu

Mire Kavu gets +1/+1 as long as you control a Swamp.

Slinking Serpent

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