msem-instigator

Trample
When Reckless Exemplar attacks, if its power is greater than its base power, target creature an opponent controls can't block this turn.

Lionize {1}{B} ({1}{B}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following abilities until end of turn. You may cast this card on a later turn from exile.)
Flying, lifelink
Whenever this creature deals combat damage to a player, remove all counters from target permanent they control or protect.

{2}{B}: Reclaimed Kalak gains indestructible until end of turn.
Revive {3}{W} ({3}{W}, 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.)

When Reclamation Sage enters, you may destroy target artifact or enchantment.

Flash
{U}, Return another creature you control to its owner's hand: Reclusive Archmage can't be blocked this turn and gains hexproof until end of turn. Activate only once each turn.

As an additional cost to cast this spell, pay {2} or sacrifice a creature.
Menace

When Recon Drone enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle. Then if you did, put a card from your hand on the bottom of your library.

When Reconnaissance Expert enters, mill four cards.
When Reconnaissance Expert dies, return target noncreature permanent card from your graveyard to your hand.

Deception {U} ({U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever a Pirate or Rogue you control deals combat damage to a player, rediscover a Pirate or Rogue card. (Look at the top card of your library. You may reveal it and put it into your hand if it's a Pirate or Rogue. Otherwise, put it back or into your graveyard.)

Whenever Recurring Abomination deals combat damage to an opponent, you may put target creature card with mana value 3 or less from a graveyard onto the battlefield under your control.
{4}{B}{B}: Return Recurring Abomination from your graveyard to the battlefield tapped.

When Recursion Runner enters, create a Function token with “If this spell isn't a copy, copy it. You may choose new targets for the copy.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Trample, haste
When Red Pelt Hart deals combat damage to a player, return it to its owner's hand.
At the beginning of your end step, sacrifice Red Pelt Hart.

First strike
Whenever an opponent casts a noncreature spell, you gain 2 life.

As Reflective Stalker enters, choose a noncreature card name.
When Reflective Stalker enters, if it was cast, create a token that's a copy of it.
Spells your opponents cast with the chosen name cost {2} more to cast.

Flying, lifelink

Menace
Regal Dragoon gets +1/+1 as long as you control a legendary creature.

Menace

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.

Whenever a creature dealt damage by Rei's Betrayer this turn dies, you gain life equal to that creature's toughness.

When Rei's Cultivator enters, create a green Aura enchantment token named Sowing Spring attached to target land. The token has enchant land, “Enchanted land's name is Flowering Expanse” and “Whenever enchanted land is tapped for mana, add one mana of any color.”

Reinbreaker Behemoth attacks each combat if able.

Harmony — Destroy target artifact or enchantment.
When Rejoicing Aristocrats enters, harmonize. (Trigger up to one harmony of one permanent you control.)

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.

Vigilance
When this creature enters, create a 1/1 blue Bird creature token with flying.