Sun-Crowned Hunters

Enrage — Whenever this creature is dealt damage, it deals 3 damage to target opponent or planeswalker.

Wrathful Raptors

Trample
Whenever a Dinosaur you control is dealt damage, it deals that much damage to any target that isn't a Dinosaur.

Fiendlash

Equipped creature gets +2/+0 and has reach.
Whenever equipped creature is dealt damage, it deals damage equal to its power to target player or planeswalker.
Equip {2}{R}

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 Noble or a creature it's paired with is dealt damage, Donna Noble deals that much damage to target opponent.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Wrathful Red Dragon

Flying
Whenever a Dragon you control is dealt damage, it deals that much damage to any target that isn't a Dragon.

Stuffy Doll

Indestructible
As this creature enters, choose a player.
Whenever this creature is dealt damage, it deals that much damage to the chosen player.
{T}: This creature deals 1 damage to itself.

Kazarov, Sengir Pureblood

Flying
Whenever a creature an opponent controls is dealt damage, put a +1/+1 counter on Kazarov.
{3}{R}: Kazarov deals 2 damage to target creature.

Coalhauler Swine

Whenever this creature is dealt damage, it deals that much damage to each player.

Silverclad Ferocidons

Enrage — Whenever this creature is dealt damage, each opponent sacrifices a permanent of their choice.

Brash Taunter

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

Oros, the Avenger

Flying
Whenever Oros deals combat damage to a player, you may pay {2}{W}. If you do, Oros deals 3 damage to each nonwhite creature.

Blazing Sunsteel

Equipped creature gets +1/+0 for each opponent you have.
Whenever equipped creature is dealt damage, it deals that much damage to any target.
Equip {4}

Pain for All

Enchant creature you control
When this Aura enters, enchanted creature deals damage equal to its power to any other target.
Whenever enchanted creature is dealt damage, it deals that much damage to each opponent.