msem-instigator

Flash
Flying, protection from sorceries
You may look at the top card of your library any time.
You may cast spells from the top of your library as long as it's not your main phase.

When R-12 Lone Digger enters, it deals 3 damage to target player or planeswalker.

Flying
Whenever a creature you don't control deals damage, its controller sacrifices it unless that player pays {2}.

When Ragantiar enters, mill five cards.
{3}{B}, Sacrifice a creature: Return target creature card with power X or less from your graveyard to the battlefield, where X is 1 plus the sacrificed creature's power.

Flying, trample
Whenever Raidragos' Avenger deals combat damage to a player, create a 5/5 red Dragon creature token with flying.
Creatures you control get +1/+0 for each Dragon you control.

When Rampaging Xiangshe enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Each creature you control with a +1/+1 counter on it has trample.

Draw two cards. You may play an additional land this turn.
Coalesce {5}{G}{U} (You may cast this from your graveyard for {5}{G}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Return up to three target land cards from your graveyard to your hand.
Coalesce {6}{G} (You may cast this from your graveyard for {6}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Whenever Reclamation Grovesculptor enters or attacks, put a growth counter on target noncreature permanent. It becomes a colorless Forest land and loses all other card types and land types.

When Reha, Entropy's Call enters, you may search your library for any number of land cards with different names and exile them with harvest counters, then shuffle.
At the beginning of your upkeep, you may put a card that you own in exile with a harvest counter on it at random onto the battlefield tapped.

Reinbreaker Behemoth attacks each combat if able.

Trample, haste
When Rejuvenating Elemental enters, remove up to X -1/-1 counters from among creatures you control. Rejuvenating Elemental gets +1/+1 until end of turn for each counter removed this way.

Deploy 3 (As this enters, you may tap any number of other creatures you control with total power 3 or more.)
When Relief Battalion enters deployed, draw a card.

Deploy 4 (As this enters, you may tap any number of other creatures you control with total power 4 or more.)
When Revolutionary Recruiters enters deployed, gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

Whenever Rhudai Swathcutter attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Hexproof from mana value 3 or less
{W}: Rhysta of the Roses gains lifelink until end of turn.
{B}: Rhysta of the Roses gains menace until end of turn.

Flying
Whenever Rimebreath Tyrant attacks, you may discard a card. When you do, tap target creature. It doesn't untap during its controller's next untap step.

Menace
Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, each opponent discards a card.

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

Trample
When Rundfora Communionist enters, return a creature you control to its owner's hand.
Creature spells you cast cost {1} less to cast.

Whenever Rustshell Mantis is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)

Flying
Legendary spells you cast cost {1} less to cast.
{W}{U}{B}{R}{G}: Search your library or graveyard for a legendary card, reveal that card, and put it into your hand. If you searched your library this way, shuffle.

Flying, prowess
Once each turn, when you cast a noncreature spell, you may create a 4/4 blue Sphinx Wizard creature token with flying, then scry 1.
{2}{U}{U}, Discard Sage of the Hereafter: Create a 4/4 blue Sphinx Wizard creature token with flying, then scry 1. Activate only as a sorcery.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Sagi's Revenant deals combat damage to a player, that player discards a card.
Whenever an opponent discards a land card, you may have target creature get -2/-2 until end of turn.