msem-instigator

If a creature an opponent controls would die, exile it instead.
Whenever Rocket Poacher deals combat damage to a player, put a card exiled with it onto the battlefield under your control.

Trample
Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Rockpounding Saurian enters, if tribute wasn't paid, you may destroy up to one target artifact, up to one target land and up to one target Fortress.

At the beginning of combat on each of your turns, you may sacrifice a land or exile a land card from your graveyard. If you do, create two 1/1 red Goblin creature tokens with haste. Exile those tokens at the beginning of the next end step.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its costs.)
{1}{R}, Discard a red card: Roggar deals 2 damage to any target. This damage can't be prevented.
{2}{R}, Exile a red card from your graveyard: Create two tapped 1/1 red Elemental creature tokens.

Choose three. You may choose the same mode more than once.
• Return target creature with mana value 2 or less to its owner's hand.
• Scry 1, then draw a card, then discard a card.
• Target creature gets -2/-0 until end of turn and attacks this turn if able.

Create a number of 3/3 green Elemental creature tokens equal to the number of differently named lands you control.
Fuse (You may cast one or both halves of this card from your hand.)

Target opponent looks at the top six cards of your library and separates them into a face-down pile and a face-up pile. Choose a pile, then play any number of cards from it without paying their mana costs. Put the rest of the cards into your graveyard.

Pay 3 life: Put a +1/+1 counter on target creature.

For each nontoken enchantment you control, conjure a duplicate of it into your hand. Until the end of your next turn, you have no maximum hand size.
Exile Root Duplication.

(Activate each submodule once as a sorcery. When this enters, activate one submodule for free.)
{G}{G}{G}: Seed
Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.
{G}{G}{G}: Soil
Destroy target noncreature permanent.
{G}{G}{G}: Stem
Root Module gains “You may play an additional land on each of your turns.” and “Lands you control are every basic land type in addition to their other types.”

When Rootbound Awakener enters, create a green Aura enchantment token named Vivification attached to target creature or land. The token has enchant creature or land and “Enchanted permanent is a creature with base power and toughness 5/5 in addition to its other types.”

Defender
As long as you control an enchantment, Rooted Cavalier has vigilance and can attack as though it didn't have defender.

{6}: Create a 1/1 black Worm creature token.

Create a 1/1 green Saproling creature token for each nonland permanent card in your graveyard.

When Rotting Greatwurm dies, put three +1/+1 counters on target creature you control.
Fleeting {2}{G} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Destroy target land. Create a 2/2 black Zombie creature token.

Once each turn, when Rova, the Fleshweaver enters or you attack with one or more Horrors, you may put a +1/+1 counter on each creature you control. Then if Rova isn't a token, untap each land you control. Until your next turn, you may cast permanent spells as though they had flash.
{2}{G}{G}, Discard Rova: Create a token that's a copy of Rova, the Fleshweaver, except it's 4/4 and isn't legendary. Activate only as a sorcery.

When Roving Chaplains enters, create two 1/1 white Spirit creature tokens with flying.
{W}, Tap another untapped creature you control: Tap target nonland permanent an opponent controls.

Gain control of up to two target creatures until end of turn. Untap them. They gain haste until end of turn.
Menagerie — If there are five or more creature types among creatures you control, untap all creatures you control. Until end of turn, they gain “{T}: This creature fights another target creature.”

[+1]: Tap target permanent. Put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
[0]: Put target artifact, instant, or sorcery card from your graveyard on top of your library. If you have an insight counter, you may return that card to your hand instead.
[0]: You get an insight counter.
[–1]: Target creature can't be blocked this turn. Until end of turn, whenever that creature deals damage to an opponent, you draw a card.

Vigilance
When Roya Ritualist enters or whenever you cast a spell, if {G}{U} was spent to cast it, draw a card, then you may put a land card from your hand onto the battlefield tapped. Put a +1/+1 counter on Roya Ritualist.

Flying
Whenever Rubble Scavenger deals combat damage to a player, you may return target artifact card with mana value 4 or less from your graveyard to the battlefield.

Trample
Whenever Ruinous Glutton deals combat damage to a player, destroy target artifact or enchantment that player controls.

{1}, Sacrifice Ruinous Proselyte: Destroy target artifact or nonbasic land.

Ruins Monitor can't be blocked by more than one creature.