Boon of Emrakul

Enchant creature
Enchanted creature gets +3/-3.

Blood Mist

At the beginning of combat on your turn, target creature you control gains double strike until end of turn.

Anthem of Rakdos

Whenever a creature you control attacks, it gets +2/+0 until end of turn and Anthem of Rakdos deals 1 damage to you.
Hellbent — As long as you have no cards in hand, if a source you control would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Demonic Embrace

Enchant creature
Enchanted creature gets +3/+1, has flying, and is a Demon in addition to its other types.
You may cast Demonic Embrace from your graveyard by paying 3 life and discarding a card in addition to paying its other costs.

Caverns of Despair

No more than two creatures can attack each combat.
No more than two creatures can block each combat.

Hooded Blightfang

Deathtouch
Whenever a creature you control with deathtouch attacks, each opponent loses 1 life and you gain 1 life.
Whenever a creature you control with deathtouch deals damage to a planeswalker, destroy that planeswalker.

Burst of Speed

Creatures you control gain haste until end of turn. (They can attack and {T} even if they just came under your control.)

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Bloodsworn Steward

Flying
Commander creatures you control get +2/+2 and have haste.

Akki War Paint

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets +2/+1.

Warrior's Oath

Take an extra turn after this one. At the beginning of that turn's end step, you lose the game.

Eater of Virtue

Whenever equipped creature dies, exile it.
Equipped creature gets +2/+0.
As long as a card exiled with Eater of Virtue has flying, equipped creature has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.
Equip {1}

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Crystal Slipper

Equipped creature gets +1/+0 and has haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Battlemage's Bracers

Equipped creature has haste.
Whenever an ability of equipped creature is activated, if it isn't a mana ability, you may pay {1}. If you do, copy that ability. You may choose new targets for the copy.
Equip {2}

Curse of Stalked Prey

Enchant player
Whenever a creature deals combat damage to enchanted player, put a +1/+1 counter on that creature.

Curse of Opulence

Enchant player
Whenever enchanted player is attacked, create a Gold token. Each opponent attacking that player does the same. (A Gold token is an artifact with "Sacrifice this artifact: Add one mana of any color.")

Colossus Hammer

Equipped creature gets +10/+10 and loses flying.
Equip {8} ({8}: Attach to target creature you control. Equip only as a sorcery.)

Berserkers' Onslaught

Attacking creatures you control have double strike.

Dictate of the Twin Gods

Flash
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Break Through the Line

{R}: Target creature with power 2 or less gains haste until end of turn and can't be blocked this turn.

Blazing Specter

Flying, haste
Whenever Blazing Specter deals combat damage to a player, that player discards a card.

Falthis, Shadowcat Familiar

Commanders you control have menace and deathtouch.
Partner (You can have two commanders if both have partner.)

Bloodlust Inciter

{T}: Target creature gains haste until end of turn. (It can attack and {T} this turn.)

Cartouche of Zeal

Enchant creature you control
When Cartouche of Zeal enters, target creature can't block this turn.
Enchanted creature gets +1/+1 and has haste. (It can attack and {T} no matter when it came under your control.)

Boots of Speed

Dark Favor

Enchant creature
When Dark Favor enters, you lose 1 life.
Enchanted creature gets +3/+1.

Battle-Rage Blessing

Target creature gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Bitter Feud

As Bitter Feud enters, choose two players.
If a source controlled by one of the chosen players would deal damage to the other chosen player or a permanent that player controls, that source deals double that damage to that player or permanent instead.

Archetype of Aggression

Creatures you control have trample.
Creatures your opponents control lose trample and can't have or gain trample.

Henrika, Infernal Seer

Flying, deathtouch, lifelink
{1}{B}{B}: Each creature you control with flying, deathtouch, and/or lifelink gets +1/+0 until end of turn.

Henrika Domnathi

Flying
At the beginning of combat on your turn, choose one that hasn't been chosen —
• Each player sacrifices a creature of their choice.
• You draw a card and you lose 1 life.
• Transform Henrika Domnathi.

Henrika Domnathi // Henrika, Infernal Seer

Last Chance

Captive Audience

Captive Audience enters under the control of an opponent of your choice.
At the beginning of your upkeep, choose one that hasn't been chosen —
• Your life total becomes 4.
• Discard your hand.
• Each opponent creates five 2/2 black Zombie creature tokens.

Agent of the Shadow Thieves

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, put a +1/+1 counter on this creature. It gains deathtouch and indestructible until end of turn."