Donna Noble

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
Whenever Donna or a creature it's paired with is dealt damage, Donna deals that much damage to target opponent.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Phyrexian Vindicator

Flying
If damage would be dealt to Phyrexian Vindicator, prevent that damage. When damage is prevented this way, Phyrexian Vindicator deals that much damage to any other target.

Barbed Servitor

Indestructible
When Barbed Servitor enters, suspect it. (It has menace and can't block.)
Whenever Barbed Servitor deals combat damage to a player, you draw a card and you lose 1 life.
Whenever Barbed Servitor is dealt damage, target opponent loses that much life.

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Supernatural Stamina

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Piru, the Volatile

Flying, lifelink
At the beginning of your upkeep, sacrifice Piru, the Volatile unless you pay {R}{W}{B}.
When Piru dies, it deals 7 damage to each nonlegendary creature.

Demonic Gifts

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield under its owner's control."

Armor of Shadows

Until end of turn, target creature gets +1/+0 and gains indestructible. (Damage and effects that say "destroy" don't destroy it.)

Gift of Immortality

Enchant creature
When enchanted creature dies, return that card to the battlefield under its owner's control. Return Gift of Immortality to the battlefield attached to that creature at the beginning of the next end step.

Spark Trooper

Trample, lifelink, haste
At the beginning of the end step, sacrifice Spark Trooper.

Boros Reckoner

Whenever Boros Reckoner is dealt damage, it deals that much damage to any target.
{R/W}: Boros Reckoner gains first strike until end of turn.

Feign Death

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Pariah

Enchant creature
All damage that would be dealt to you is dealt to enchanted creature instead.

Felidar Sovereign

Vigilance (Attacking doesn't cause this creature to tap.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your upkeep, if you have 40 or more life, you win the game.

Undying Malice

Vish Kal, Blood Arbiter

Flying, lifelink
Sacrifice a creature: Put X +1/+1 counters on Vish Kal, Blood Arbiter, where X is the sacrificed creature's power.
Remove all +1/+1 counters from Vish Kal: Target creature gets -1/-1 until end of turn for each +1/+1 counter removed this way.

Kroxa and Kunoros

Vigilance, menace, lifelink
Whenever Kroxa and Kunoros enters or attacks, you may exile five cards from your graveyard. When you do, return target creature card from your graveyard to the battlefield.

Stalking Vengeance

Haste
Whenever another creature you control dies, it deals damage equal to its power to target player or planeswalker.

Brion Stoutarm

Lifelink
{R}, {T}, Sacrifice another creature: Brion Stoutarm deals damage equal to the sacrificed creature's power to target player or planeswalker.

Stormwild Capridor

Flying
If noncombat damage would be dealt to Stormwild Capridor, prevent that damage. Put a +1/+1 counter on Stormwild Capridor for each 1 damage prevented this way.

Rhox Faithmender

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
If you would gain life, you gain twice that much life instead.

Faith's Reward

Return to the battlefield all permanent cards in your graveyard that were put there from the battlefield this turn.

Nested Ghoul

Whenever a source deals damage to Nested Ghoul, create a 2/2 black Phyrexian Zombie creature token.

Venerable Warsinger

Vigilance, trample
Whenever Venerable Warsinger deals combat damage to a player, you may return target creature card with mana value X or less from your graveyard to the battlefield, where X is the amount of damage Venerable Warsinger dealt to that player.

Disciple of Bolas

When Disciple of Bolas enters, sacrifice another creature. You gain X life and draw X cards, where X is that creature's power.

Storm Herd

Create X 1/1 white Pegasus creature tokens with flying, where X is your life total.

Zurgo Helmsmasher

Haste
Zurgo Helmsmasher attacks each combat if able.
During your turn, Zurgo Helmsmasher has indestructible.
Whenever a creature dealt damage by Zurgo Helmsmasher this turn dies, put a +1/+1 counter on Zurgo Helmsmasher.

Livewire Lash

Equipped creature gets +2/+0 and has "Whenever this creature becomes the target of a spell, this creature deals 2 damage to any target."
Equip {2}

Brash Taunter

Indestructible
Whenever Brash Taunter is dealt damage, it deals that much damage to target opponent.
{2}{R}, {T}: Brash Taunter fights another target creature.