Flying
When this creature enters, until end of turn, target creature you control gets +X/+0 and target creature an opponent controls gets -0/-X, where X is the number of artifacts you control.

Morbid Hunger deals 3 damage to any target. You gain 3 life.
Flashback

Flying
Exalted
Whenever Nefarox attacks alone, defending player sacrifices a creature of their choice.

Whenever this creature attacks, up to five target creatures each get -1/-1 until end of turn.

If a white creature is attacking, you may pay rather than pay this spell's mana cost.
Exile target attacking creature. Create a token that's a copy of that creature. Exile it at the beginning of the next end step.

Enchant creature or land
Enchanted permanent has "At the beginning of your end step, sacrifice this permanent and attach Nettlevine Blight to a creature or land you control."

Search target player's library for X cards, where X is the number of cards in your hand, and exile them. Then that player shuffles.
Epic

Flying
As long as it's nightime, Nightmare Moon gets +2/+2 and has menace.
: Transform Nightmare Moon. Anypony may activate this ability or help pay the cost. When they do, they become your friend.

Fear
Suspend 7 —
Whenever a card is put into an opponent's graveyard from anywhere, if this card is suspended, you may remove a time counter from this card.

Whenever you tap a Swamp for mana, add an additional .
: This creature gets +1/+1 until end of turn.

This creature enters with five +1/+1 counters on it.
Whenever a player casts a spell, remove a +1/+1 counter from this creature. If you do, create a 2/2 black Zombie creature token.

Flying
When this creature dies, you may destroy target creature with mana value 3 or less.

Menace
When this creature enters, you may destroy another target creature. If a creature is destroyed this way, you gain life equal to its toughness.

Skip your draw step.
Whenever you play a card, draw a card.
Your maximum hand size is two.

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

Creature cards in graveyards can attack and block as though they were on the battlefield, can block or be blocked only by creature cards in graveyards, are Zombies in addition to their other types, and have undeathtouch. (If they would deal damage to a creature card, exile that creature card instead.)
Creature cards in your graveyard have haste.

Exile all creatures. Empower Jace X, where X is the number of creatures exiled this way.

Flying
When this creature enters, destroy target creature an opponent controls.
Whenever a creature an opponent controls dies, exile it and put a +1/+1 counter on each Vampire you control.

When this creature enters, investigate.
Whenever you sacrifice a Clue, target opponent gets two poison counters.

When this creature enters, you draw two cards and you lose 2 life.

Destroy target nonblack creature. You gain 3 life.

Extort
Other creatures you control have extort. (If a creature has multiple instances of extort, each triggers separately.)

Destroy all creatures target opponent controls. You lose 2 life for each creature destroyed this way.

Whenever this creature attacks, put target creature card from defending player's graveyard onto the battlefield under your control.
Encore

When this creature enters, target creature you control gets +2/+0 and gains indestructible until end of turn.
Swampcycling

Fear
At the beginning of your upkeep, you may search your library for a Rat card, reveal it, put it into your hand, then shuffle.

Each player sacrifices a creature of their choice. Create an X/X black Demon creature token with flying, where X is the total power of the creatures sacrificed this way.

When this creature enters, target creature an opponent controls gets -3/-3 until end of turn. If that creature is legendary, its controller loses 3 life.
When the Ring tempts you, return this card from your graveyard to your hand.