Ranging Raptors

Enrage — Whenever this creature is dealt damage, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Trapjaw Tyrant

Enrage — Whenever this creature is dealt damage, exile target creature an opponent controls until this creature leaves the battlefield.

Rite of Passage

Whenever a creature you control is dealt damage, put a +1/+1 counter on it. (It must survive the damage to get the counter.)

Ripjaw Raptor

Enrage — Whenever this creature is dealt damage, draw a card.

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.

Cacophodon

Enrage — Whenever this creature is dealt damage, untap target permanent.

Needletooth Raptor

Enrage — Whenever this creature is dealt damage, it deals 5 damage to target creature an opponent controls.

Truefire Captain

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever this creature is dealt damage, it deals that much damage to target player.

Wrathful Raptors

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

Zalto, Fire Giant Duke

Trample
Whenever Zalto is dealt damage, venture into the dungeon. (Enter the first room or advance to the next room.)

Sprouting Phytohydra

Defender (This creature can't attack.)
Whenever this creature is dealt damage, you may create a token that's a copy of this creature.

Metropolis Reformer

Flying, vigilance
You have hexproof.
Whenever this creature is dealt damage, you gain that much life.

Feldon, Ronom Excavator

Haste
Feldon can't block.
Whenever Feldon is dealt damage, exile that many cards from the top of your library. Choose one of them. Until the end of your next turn, you may play that card.

Howlpack Avenger

Whenever a permanent you control is dealt damage, this creature deals that much damage to any target.
{1}{R}: This creature gets +2/+0 until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Ill-Tempered Loner

Whenever this creature is dealt damage, it deals that much damage to any target.
{1}{R}: This creature gets +2/+0 until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Ill-Tempered Loner // Howlpack Avenger

Wayta, Trainer Prodigy

Haste
{2}{G}, {T}: Target creature you control fights another target creature. This ability costs {2} less to activate if it targets two creatures you control.
If a creature you control being dealt damage causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Arcbond

Choose target creature. Whenever that creature is dealt damage this turn, it deals that much damage to each other creature and each player.

Hungering Hydra

This creature enters with X +1/+1 counters on it.
This creature can't be blocked by more than one creature.
Whenever this creature is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)

Silverclad Ferocidons

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

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}

Spitemare

Whenever this creature is dealt damage, it deals that much damage to any target.

Boros Reckoner

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

Forerunner of the Empire

When this creature enters, you may search your library for a Dinosaur card, reveal it, then shuffle and put that card on top.
Whenever a Dinosaur you control enters, you may have this creature deal 1 damage to each creature.

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.

Urban Daggertooth

Vigilance
Enrage — Whenever this creature is dealt damage, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Apex Altisaur

When this creature enters, it fights up to one target creature you don't control.
Enrage — Whenever this creature is dealt damage, it fights up to one target creature you don't control.

Polyraptor

Enrage — Whenever this creature is dealt damage, create a token that's a copy of this creature.

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.

Siegehorn Ceratops

Enrage — Whenever this creature is dealt damage, put two +1/+1 counters on it. (It must survive the damage to get the counters.)

Hornet Nest

Defender (This creature can't attack.)
Whenever this creature is dealt damage, create that many 1/1 green Insect creature tokens with flying and deathtouch. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

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.)

Broodhatch Nantuko

Whenever this creature is dealt damage, you may create that many 1/1 green Insect creature tokens.
Morph {2}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Snapping Sailback

Flash
Enrage — Whenever this creature is dealt damage, put a +1/+1 counter on it. (It must survive the damage to get the counter.)

Vrondiss, Rage of Ancients

Enrage — Whenever Vrondiss is dealt damage, you may create a 5/4 red and green Dragon Spirit creature token with "When this token deals damage, sacrifice it."
Whenever you roll one or more dice, you may have Vrondiss deal 1 damage to itself.

Flumph

Defender, flying
Whenever this creature is dealt damage, you and target opponent each draw a card.

Sporeweb Weaver

Reach, hexproof from blue
Whenever this creature is dealt damage, you gain 1 life and create a 1/1 green Saproling creature token.

Bellowing Aegisaur

Enrage — Whenever this creature is dealt damage, put a +1/+1 counter on each other creature you control.

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}

Overgrown Armasaur

Enrage — Whenever this creature is dealt damage, create a 1/1 green Saproling creature token.