msem-instigator

Starting with you, each player either passes or reveals the top card of their library. Each player that revealed a card this way pays life equal to its mana value. If a player can't, that player passes. Then each player who hasn't passed yet puts that card into their hand. Repeat this process until each player has passed.

{T}: Target creature gains haste until end of turn.
{1}{R}, {T}, Sacrifice a Human: Create a token that's a copy of the sacrificed creature, except it's a 3/2 colorless Horror. It gains haste until end of turn. Activate only as a sorcery.

Whenever you cast a noncreature spell, you may put a progress counter on Reckless Research.
[progress 2+] At the beginning of your end step, mill two cards.
[progress 7+] At the beginning of your upkeep, choose target instant or sorcery card in your graveyard. You may cast it from your graveyard this turn.
At the beginning of your upkeep, choose target instant or sorcery card in your graveyard. You may cast it from your graveyard this turn.

Trial 6 (As you cast this spell, an opponent of your choice may pay 6 life. If they don't, they fail the trial.)
Flying
When Reckoner of Man enters, if the trial was failed, it deals 3 damage to each creature you don't control.

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.

Whenever a creature you control deals combat damage to an opponent or planeswalker, put a technology counter on Reclamation Project.
Remove X technology counters from Reclamation Project: You may cast target artifact or creature card with mana value X from your graveyard this turn. That creature enters as an artifact in addition to its other types. X can't be 0.

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.

Reclusive Copse enters tapped.
{T}: Add {B} or {G}.
{1}{B}{G}: Until end of turn, Reclusive Copse becomes an Insect creature with deathtouch in addition to its other types.
Scavenge {B}{G}

When Recognification Process enters and at the beginning of your upkeep, create a token that's a copy of target artifact you control, then sacrifice an artifact.

Flash
Creatures your opponents control have base power and toughness 1/1.
Fleeting {1}{W}{W} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Menace
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Return target artifact, enchantment, or planeswalker card with mana value 3 or less from your graveyard to the battlefield.

Choose one —
• Counter target spell unless its controller pays {2}.
• Draw a card.

Destroy target noncreature permanent. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Flash
Prowess
When Reconstructed Adept enters, target instant or sorcery card in your graveyard gains agonize until end of turn. (You may cast it by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile that card.)

Flying, lifelink
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Recreator of Myths attacks, you may cast target instant or sorcery spell from your graveyard. If you do, exile that card instead of putting it into your graveyard as it resolves.

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.)

When Red Flower Assassin enters, destroy target creature.
Revive {5}{B} ({5}{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.)

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
Redeye Commando's power is equal to twice the number of artifacts you control.
Redeye Commando attacks each turn if able.
Whenever Redeye Commando attacks, if its power is 6 or greater, it gains menace and trample until end of turn.

Counter target spell unless its controller pays its mana cost. (For example, if a spell costs {1}{U}{U}, its controller must pay {1}{U}{U}.)

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

Target player sacrifices a creature. Then you gain 3 life if that player doesn't control any creatures.