Vrondiss, Rage of Ancients

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

Polyraptor

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

Cacophodon

Enrage — Whenever Cacophodon is dealt damage, untap target permanent.

Apex Altisaur

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

Silverclad Ferocidons

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

Needletooth Raptor

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

Ranging Raptors

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

Indoraptor, the Perfect Hybrid

Bloodthirst X (This creature enters with X +1/+1 counters on it, where X is the damage dealt to your opponents this turn.)
Menace
Enrage — Whenever Indoraptor, the Perfect Hybrid is dealt damage, choose an opponent at random. Indoraptor deals damage equal to its power to that player unless they sacrifice a nontoken creature of their choice.

Ravenous Daggertooth

Enrage — Whenever Ravenous Daggertooth is dealt damage, you gain 2 life.

Ripjaw Raptor

Enrage — Whenever Ripjaw Raptor is dealt damage, draw a card.

Frilled Deathspitter

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

Snapping Sailback

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