Mishra, Claimed by Gix

Whenever you attack, each opponent loses X life and you gain X life, where X is the number of attacking creatures. If Mishra, Claimed by Gix and a creature named Phyrexian Dragon Engine are attacking, and you both own and control them, exile them, then meld them into Mishra, Lost to Phyrexia. It enters tapped and attacking.

Phyrexian Dragon Engine

Double strike
When Phyrexian Dragon Engine enters from your graveyard, you may discard your hand. If you do, draw three cards.
Unearth {3}{R}{R}
(Melds with Mishra, Claimed by Gix.)

Urabrask the Hidden

Creatures you control have haste.
Creatures your opponents control enter tapped.

Gixian Puppeteer

Whenever you draw your second card each turn, each opponent loses 2 life and you gain 2 life.
When Gixian Puppeteer dies, return another target creature card with mana value 3 or less from your graveyard to the battlefield.

Activated Sleeper

Flash
You may have Activated Sleeper enter as a copy of any creature card in a graveyard that was put there from the battlefield this turn, except it's a Phyrexian in addition to its other types.

Priest of Urabrask

When Priest of Urabrask enters, add {R}{R}{R}.

Thrashing Frontliner

Trample
Whenever Thrashing Frontliner attacks a battle, it gets +1/+1 until end of turn.

Song of Totentanz

Create X 1/1 black Rat creature tokens with "This creature can't block." Creatures you control gain haste until end of turn.

Krenko, Tin Street Kingpin

Whenever Krenko, Tin Street Kingpin attacks, put a +1/+1 counter on it, then create a number of 1/1 red Goblin creature tokens equal to Krenko's power.

Harried Dronesmith

At the beginning of combat on your turn, create a 1/1 colorless Thopter artifact creature token with flying. It gains haste until end of turn. Sacrifice it at the beginning of your next end step.

Kardur, Doomscourge

When Kardur, Doomscourge enters, 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.

Legion Warboss

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
At the beginning of combat on your turn, create a 1/1 red Goblin creature token. That token gains haste until end of turn and attacks this combat if able.

Siege-Gang Commander

When Siege-Gang Commander enters, create three 1/1 red Goblin creature tokens.
{1}{R}, Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to any target.

Siege-Gang Lieutenant

Lieutenant — At the beginning of combat on your turn, if you control your commander, create two 1/1 red Goblin creature tokens. Those tokens gain haste until end of turn.
{2}, Sacrifice a Goblin: Siege-Gang Lieutenant deals 1 damage to any target.

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.

Tilonalli's Summoner

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Whenever Tilonalli's Summoner attacks, you may pay {X}{R}. If you do, create X 1/1 red Elemental creature tokens that are tapped and attacking. At the beginning of the next end step, exile those tokens unless you have the city's blessing.

Squee, Dubious Monarch

Haste
Whenever Squee, Dubious Monarch attacks, create a 1/1 red Goblin creature token that's tapped and attacking.
You may cast Squee, Dubious Monarch from your graveyard by paying {3}{R} and exiling four other cards from your graveyard rather than paying its mana cost.

Terminate

Destroy target creature. It can't be regenerated.

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Hellrider

Haste
Whenever a creature you control attacks, Hellrider deals 1 damage to the player or planeswalker it's attacking.

Sling-Gang Lieutenant

When Sling-Gang Lieutenant enters, create two 1/1 red Goblin creature tokens.
Sacrifice a Goblin: Target player loses 1 life and you gain 1 life.

Bedevil

Destroy target artifact, creature, or planeswalker.

Gnawing Crescendo

Creatures you control get +2/+0 until end of turn. Whenever a nontoken creature you control dies this turn, create a 1/1 black Rat creature token with "This creature can't block."

Battle Hymn

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Dragon Fodder

Create two 1/1 red Goblin creature tokens.

Hazardous Blast

Hazardous Blast deals 1 damage to each creature your opponents control. Creatures your opponents control can't block this turn.

Krenko's Command

Tempt with Vengeance

Tempting offer — Create X 1/1 red Elemental creature tokens with haste. Each opponent may create X 1/1 red Elemental creature tokens with haste. For each opponent who does, create X 1/1 red Elemental creature tokens with haste.

Tempt with Immortality

Tempting offer — Return a creature card from your graveyard to the battlefield. Each opponent may return a creature card from their graveyard to the battlefield. For each opponent who does, return a creature card from your graveyard to the battlefield.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Kolaghan Warmonger

Haste
Whenever Kolaghan Warmonger attacks, look at the top six cards of your library. You may reveal a Dragon card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Bathe in Dragonfire

Bathe in Dragonfire deals 4 damage to target creature.

Brimstone Dragon

Dragon Breath

Enchant creature
Enchanted creature has haste.
{R}: Enchanted creature gets +1/+0 until end of turn.
When a creature with mana value 6 or greater enters, you may return Dragon Breath from your graveyard to the battlefield attached to that creature.

Dragon Hatchling

Flying
{R}: Dragon Hatchling gets +1/+0 until end of turn.

Dragonloft Idol

As long as you control a Dragon, Dragonloft Idol gets +1/+1 and has flying and trample.

Phyrexian Debaser

Flying
{T}, Sacrifice Phyrexian Debaser: Target creature gets -2/-2 until end of turn.

Phyrexian Defiler

{T}, Sacrifice Phyrexian Defiler: Target creature gets -3/-3 until end of turn.

Phyrexian Denouncer

{T}, Sacrifice Phyrexian Denouncer: Target creature gets -1/-1 until end of turn.

Phyrexian Broodlings

{1}, Sacrifice a creature: Put a +1/+1 counter on Phyrexian Broodlings.

Phyrexian Ghoul

Sacrifice a creature: Phyrexian Ghoul gets +2/+2 until end of turn.

Mountain

Swamp

Jagged Barrens

Jagged Barrens enters tapped.
When Jagged Barrens enters, it deals 1 damage to target opponent.
{T}: Add {B} or {R}.

Geothermal Bog

({T}: Add {B} or {R}.)
Geothermal Bog enters tapped.

Shadowblood Ridge

Den of the Bugbear

If you control two or more other lands, Den of the Bugbear enters tapped.
{T}: Add {R}.
{3}{R}: Until end of turn, Den of the Bugbear becomes a 3/2 red Goblin creature with "Whenever this creature attacks, create a 1/1 red Goblin creature token that's tapped and attacking." It's still a land.