msem-instigator

Exile the top two cards of your library. Until end of turn, you may play those cards. Add {R} for each creature card exiled this way.

Creatures you control get +2/+1 until end of turn.
Cycling {1}{W} ({1}{W}, Discard this card: Draw a card.)

When Resting Tombs enters, exile target creature an opponent controls until this enchantment leaves the battlefield.
If a creature would die, exile it instead.
{3}{B}{B}: Exile all creature cards from all graveyards. Transform Resting Tombs. Activate only as a sorcery.

When Restless Explorer enters, search your library for a land card, reveal it, put it into your hand, then shuffle.

Return target creature card with mana value 3 or less from your graveyard to the battlefield. You gain 3 life.

Lifelink
Whenever another creature you control with a counter on it dies, return it to its owner's hand. If that creature was an Avatar, return it to the battlefield under your control instead.

When Rethia Cultivator enters, you may search your library for a land card, reveal it, put it into your hand, then shuffle.

Flying
When Reticent Possessor enters, you may attach target Aura you control to target permanent or player it could enchant.

Flash
Whenever you cast a Tale, look at the top two cards of your library. Put one into your hand and the other back on top or into your graveyard.

Counter target spell.
You may draw four cards. If you do, skip your next turn.

At the beginning of your upkeep, if a library has twenty or fewer cards left in it, return Returned Explorer from your graveyard to the battlefield tapped.

As long as there are three or more creature cards in your graveyard, Returned Minotaur gets +1/+1 and has menace.

As an additional cost to cast Reunite with Nature, sacrifice X creatures.
Create X plus one 3/1 red and green Elemental Horror creature tokens with haste and trample.

Lifelink
{W}{B}, {T}, Discard a card: Look at the top three cards of your library. You may reveal an enchantment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
When you have no cards in hand, exile Revela, then return her to the battlefield transformed under her owner's control.

[+1]: Creatures you control get +1/+0 and gain respawn until end of turn. (When one dies, if it attacked this turn, return it to its owner's hand.)
[0]: You get an emblem with “Whenever a creature you control attacks, you gain 1 life.”
[–5]: Until end of turn, Revela becomes a legendary Human Cleric Avatar creature with lifelink, indestructible, and “This creature's power and toughness are each equal to your life total.”

{B}: Revenant Shade gets +1/+1 until end of turn.

When Reverence Seeker dies, you may return another target Knight card from your graveyard to your hand.

Reverent Flame deals 3 damage to target creature. Create three Idol tokens. (They're artifacts with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Shuffle your graveyard into your library, then draw two cards.

Enchant creature
Enchanted creature can't attack, block, or crew Vehicles.

Choose target spell. If it's an instant, a sorcery, or you cast this spell from exile, copy it. You may choose new targets for the copy.
Prophecy {2}{U}{U} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

When Rework the Canvas enters, purge. (Exile two cards that share a type from graveyards. If you do, draw a card.)
Whenever one or more cards are put into exile from anywhere, you gain 2 life and scry 1.

Whenever you activate a loyalty ability of Reyhsia, Truth Chaser, you may exile a card from your hand. If you do, draw a card.
[+2]: Each player exiles up to two cards from their hand, then draws that many cards.
[0]: Until end of turn, you may play a card exiled with Reyhsia and you may spend mana as though it were mana of any color to cast that spell.
[–10]: Each player exiles all but the bottom card of their library and may play cards they own exiled this way until the end of their next turn.

[+1]: Reveal the top card of your library and put it into your hand. Then if that card wasn't legendary, discard a card.
[–X]: Return target non-Reyhsia legendary permanent card with mana value X from your graveyard to the battlefield.
[–6]: Reyhsia, the Honorless deals 4 damage to each nonlegendary creature.

Each instant and sorcery card in your hand has orchestrate. Its orchestrate cost is equal to its mana cost reduced by {2}. (You may exile those cards from your hand anytime you could cast a sorcery for their orchestrate cost. When you next resolve a spell, you may cast it from exile without paying its mana cost.)
When you cast your third spell this turn, exile Reytali, then return her to the battlefield transformed.