Duskwielder

Boast — {1}: Target opponent loses 1 life and you gain 1 life. (Activate only if this creature attacked this turn and only once each turn.)

Burning-Rune Demon

Flying
When Burning-Rune Demon enters the battlefield, you may search your library for exactly two cards not named Burning-Rune Demon that have different names. If you do, reveal those cards. An opponent chooses one of them. Put the chosen card into your hand and the other into your graveyard, then shuffle.

Balduvian Berserker

Enlist (As this creature attacks, you may tap a nonattacking creature you control without summoning sickness. When you do, add its power to this creature's until end of turn.)
When Balduvian Berserker dies, it deals damage equal to its power to any target.

Bloodsky Berserker

Whenever you cast your second spell each turn, put two +1/+1 counters on Bloodsky Berserker. It gains menace until end of turn. (It can't be blocked except by two or more creatures.)

Arni Brokenbrow

Haste
Boast — {1}: You may change Arni Brokenbrow's base power to 1 plus the greatest power among other creatures you control until end of turn. (Activate only if this creature attacked this turn and only once each turn.)

Bloodmad Vampire

Whenever Bloodmad Vampire deals combat damage to a player, put a +1/+1 counter on it.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Coalition Warbrute

Enlist (As this creature attacks, you may tap a nonattacking creature you control without summoning sickness. When you do, add its power to this creature's until end of turn.)
Trample

Escaped Null

Lifelink
Whenever Escaped Null blocks or becomes blocked, it gets +5/+0 until end of turn.

Balduvian Atrocity

Kicker {R} (You may pay an additional {R} as you cast this spell.)
Menace
When Balduvian Atrocity enters the battlefield, if it was kicked, return target creature card with mana value 3 or less from your graveyard to the battlefield. It gains haste. Sacrifice it at the beginning of the next end step.

Dragonkin Berserker

First strike
Boast abilities you activate cost {1} less to activate for each Dragon you control.
Boast — {4}{R}: Create a 5/5 red Dragon creature token with flying. (Activate only if this creature attacked this turn and only once each turn.)

Fearless Liberator

Boast — {2}{R}: Create a 2/1 red Dwarf Berserker creature token. (Activate only if this creature attacked this turn and only once each turn.)

Immersturm Raider

When Immersturm Raider enters the battlefield, you may discard a card. If you do, draw a card.

Grim Draugr

{1}{S}: Grim Draugr gets +1/+0 and gains menace until end of turn. (It can't be blocked except by two or more creatures. {S} can be paid with one mana from a snow source.)

Horde Ambusher

Whenever Horde Ambusher blocks, it deals 1 damage to you.
Morph—Reveal a red card in your hand. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Horde Ambusher is turned face up, target creature can't block this turn.

Garna, Bloodfist of Keld

Whenever another creature you control dies, draw a card if it was attacking. Otherwise, Garna, Bloodfist of Keld deals 1 damage to each opponent.

Frenzied Raider

Whenever you activate a boast ability, put a +1/+1 counter on Frenzied Raider.

Eradicator Valkyrie

Flying, lifelink, hexproof from planeswalkers
Boast — {1}{B}, Sacrifice a creature: Each opponent sacrifices a creature or planeswalker. (Activate only if this creature attacked this turn and only once each turn.)

Cleaving Reaper

Flying, trample
Pay 3 life: Return Cleaving Reaper from your graveyard to your hand. Activate only if you had an Angel or Berserker enter the battlefield under your control this turn.

Kardur, Doomscourge

When Kardur, Doomscourge enters the battlefield, until your next turn, creatures your opponents control attack each combat if able and attack a player other than you if able.
Whenever an attacking creature dies, each opponent loses 1 life and you gain 1 life.