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.)

Needletooth Raptor

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

Overgrown Armasaur

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

Imperial Ceratops

Enrage — Whenever this creature is dealt damage, you gain 2 life.

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.

Sun-Crowned Hunters

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

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.)

Raptor Hatchling

Enrage — Whenever this creature is dealt damage, create a 3/3 green Dinosaur creature token with trample.

Ripjaw Raptor

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

Polyraptor

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

Trapjaw Tyrant

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

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.

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.

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.)

Cacophodon

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

Strong, the Brutish Thespian

Ward {2}
Enrage — Whenever Strong is dealt damage, you get three rad counters and put three +1/+1 counters on Strong.
You gain life rather than lose life from radiation.

Silverclad Ferocidons

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

Ravenous Daggertooth

Bellowing Aegisaur

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

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.

Frilled Deathspitter

Enrage — Whenever this creature is dealt damage, it deals 2 damage to target opponent or planeswalker.