msem-instigator

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.

Flash

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

Hexproof
Paranoia {1}{U} (You may cast this spell for its paranoia cost when a permanent you control leaves the battlefield.)

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.)

Return target permanent to its owner's hand. Then that player discards a card.

Return target nonland permanent to its owner's hand. Then that player discards a card.

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

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

Return target creature card from your graveyard to your hand.
Draw a 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.

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.)

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.

When Red-Crowned Admiral 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 flying.

Other creatures you control get +0/+1.
{T}: Add {G}.

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.
Create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Counter target creature spell. If this spell was kicked, create a 1/1 colorless Thopter artifact creature token with flying.

Converge — Exile up to X nonland permanents you control, where X is the number of colors of mana spent to cast Reenter Orbit, then return them to the battlefield under your control.