msem-instigator

Scorching Dragonfire deals 3 damage to target creature or planeswalker. If that permanent would die this turn, exile it instead.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Scorchland Vandal attacks each combat if able.

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever a creature with wither deals combat damage to an opponent, Scorchmark Seer deals 2 damage to that player.

Flying
When Scorchpass Sovereign enters, it deals 1 damage to each creature with flying you don't control.

Counter target spell with no subtypes. Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Whenever you cast a spell, Scorned Figurant gets +1/+1 until end of turn.

Scornful Flames deals 4 damage to target player.
Dominance — Scornful Flames deals 1 damage to each creature that player controls if you control the creature with the greatest power or tied for the greatest power.

When Scorpid Sniper enters, you may have target creature get -1/-1 until end of turn.

Equipped creature gets +2/+2.
{1}: Attach Scoundrel's Aetherlock to target Rogue.
Equip {2}

Scoundreleo enters with a +1/+1 counter on it if a creature you controlled dealt combat damage to a player this turn.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever you cast a noncreature spell, add a quest counter.
Draw a card, then discard a card.
Return up to two target instant and/or sorcery cards from your graveyard to your hand.
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Scoured Mesa enters tapped.
{T}: Add {W}.
Desertcycling {1}{W} ({1}{W}, Discard this card: Search your library for a Desert card, reveal it, and put it into your hand, then shuffle.)

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Scourge of the Deadlands enters, if it engorged a creature card, each other player sacrifices a creature.

Double strike
Creatures you control have trample.
Excess noncombat damage that would be dealt by sources you control to permanents an opponent controls is dealt to that player instead.

Flying, haste
Ride {1}{R} ({1}{R}: Transform this and attach it to target creature you control without a Mount. Ride only as a sorcery.)

Flying, haste
Whenever Scourge of the Skies attacks, you may have it deal 5 damage to target creature.

As an additional cost to cast this spell, pay 3 life and sacrifice a creature.

Flying
Whenever you cast an instant or sorcery spell, Scourge of the Sun gets +1/+0 until end of turn. If you spent four or more mana to cast that spell, Scourge of the Sun gets an additional +1/+0 until end of turn.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
At the beginning of your end step, discard a card. Then draw a card if an opponent is cursed.

Look at the top five cards of your library. You may reveal a Scout or land card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Reveal the bottom four cards of your library. Choose up to one permanent card with mana value 3 or less from among them and put it onto the battlefield. Put the rest on the bottom of your library in any order.

Look at the top four cards of your library. You may put a land card from among them onto the battlefield tapped, then put the rest into your graveyard.

Target opponent reveals their hand. You choose a nonland card from it and exile that card.
Recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Target opponent reveals their hand. You choose a nonland card from it. That player exiles that card.
Each player conjures a card named Data-Point into their hand. (It's a sorcery that costs {2} with “Draw a card.”)

Prevent all damage that would be dealt by creatures this turn.