msem-instigator

Untap target creature. It gets +2/+2 and gains reach until end of turn.
Monument {3}{G} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Target creature can't be blocked this turn. It explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then you may put that card in your graveyard.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)

When Rat King enters, create two 1/1 black Rat creature tokens with “This creature can't block.”
Whenever Rat King or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Menace
When Rattled Bones dies, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Choose one or both —
• Each player sacrifices an artifact.
• Each player sacrifices an enchantment.

Enchant creature
When Ravage of Moments enters and at the beginning of your upkeep, put a -1/-1 counter on enchanted creature.

Whenever a creature you control dies, each opponent discards a card.
Revive {6}{B} ({6}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Whenever Ravencaller or another creature enters from your graveyard, create a 1/1 blue Bird creature token with flying.

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.

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.

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

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.)

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.

As an additional cost to cast this spell, you may sacrifice a creature. If you do, this spell costs {3} less to cast.
Create two 3/3 white Construct enchantment creature tokens.

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.)

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}.

{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.