msem-instigator

Whenever one or more other creatures you control deal combat damage to an opponent, choose one —
• That player discards a card at random.
• That player sacrifices a creature with toughness 4 or less.

When Ravenous Abomination enters, choose one —
• Create two Treasure tokens.
• Put a +1/+1 counter on Ravenous Abomination.

Ravenous Attraction enters with a +1/+1 counter on it.
Whenever a creature you control dies, double the number of each kind of counter on Ravenous Attraction.

When Ravenous Chupacabra enters, destroy target creature an opponent controls.

The second spell you cast each turn costs {2} less to cast.
Whenever you cast a spell, each opponent loses 1 life and you gain 1 life.

First strike, trample
Whenever a creature dealt combat damage by Ravenous Forsaken this turn dies, put a +1/+1 counter on Ravenous Forsaken.
{2}{R}: Ravenous Forsaken gets +3/+0 until end of turn.

Ravenous Grue enters with a menace counter on it.
{5}{B}{B}, Remove a menace counter from Ravenous Grue: Destroy target creature.

Ravenous Hollow enters tapped.
{T}: Add {B} or {R}.
{2}{B}{R}: Until end of turn, Ravenous Hollow becomes a Wolf creature with first strike in addition to its other types.
Scavenge {2}{B}{R}

Ravenous Hydra enters with X +1/+1 counters on it.
Whenever Ravenous Hydra deals combat damage, proliferate. (You choose any number of permanents and/or players with counters on them, then give each another kind of a counter already there.)

Double strike

When Ravenous Rats enters, target opponent discards a card.

Lifelink
When Ravenous Tarwurm enters, you may have it consume. When you do, destroy target creature with toughness 3 or less and you gain 3 life. (To consume, sacrifice another creature or exile a creature card from your graveyard.)

Tap X untapped Shamans you control: Ravik, Still-Smoke Seer deals X damage to any target and you gain X life.

When Raving Brigand enters, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)
Whenever you sacrifice an Omen, target player mills three cards.

Whenever a Survivor you control enters, you may draw a card. If you do, discard a card.

Flying
Whenever an opponent discards one or more cards, fateseal 1. (To fateseal 1, look at the top card of an opponent's library, then you may put it on the bottom of that player's library.)

Once each turn, when a creature you control enters, you may draw a card if its power is greater than each other creature's power.

You may return a land you control to its owner's hand rather than pay this spell's mana cost.
Rawthlin Market Line enters tapped.
{T}: Add {G}.

Razing Throng's power and toughness are each equal to the number of creatures you control.
Whenever one or more cards are put into exile from anywhere, create a 1/1 white Cleric creature token.
{2}{W}{W}: Exile a nonland card from a graveyard. You gain 3 life.

{T}: Add {C}.
{2}, {T}: Target creature gains haste until end of turn.

When Razorshell Marauder enters, you may sacrifice a land or exile a land card from your graveyard. When you do, target creature gets -1/-1 until end of turn and can't block this turn.

Flying
When Razorwing Champion enters, creatures you control get +1/+1 and gain vigilance until end of turn.

Creature tokens you control get +1/+1 and can block an additional creature each combat.

Death knell — You may sacrifice a nontoken creature. If you do, create a 3/3 black Spirit creature token. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)
Creatures you control dying causes their death knell to trigger. (In addition to the normal death knell trigger.)

Whenever another creature you control dies, target player loses 1 life and you gain 1 life.
{1}{B}, Sacrifice a creature: Scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)