msem-instigator

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 the battlefield, if the trial was failed, it deals 3 damage to each creature you don't control.

Flying, haste
Whenever Rhyolithic Hellkite attacks, you may sacrifice a land or exile a land card from your graveyard. If you do, put a +1/+1 counter on Rhyolithic Hellkite.

Flying
Whenever Rimebreath Tyrant attacks, you may discard a card. When you do, tap target creature. It doesn't untap during its controller's next untap step.

Flying
Whenever Rubble Scavenger deals combat damage to a player, you may return target artifact card with mana value 4 or less from your graveyard to the battlefield.

Flying
Legendary spells you cast cost {1} less to cast.
{W}{U}{B}{R}{G}: Search your library or graveyard for a legendary card, reveal that card, and put it into your hand. If you searched your library this way, shuffle.

When Sandmouth Dragon enters the battlefield, another target creature you control gets +3/+0 until end of turn.
Mirage {2}{R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Flying
{1}{R}: Sangrite Dragon gets +2/+0 until end of turn.
Sacrifice another creature: Add {R}{R}.

Flying
Whenever Scavenging Hilakites attacks, you may sacrifice another creature. When you do, Scavenging Hilakites deals damage equal to the sacrificed creature's power to any target.

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

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.

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.

Flying
Dragon spells and Adventure spells you cast cost {1} less to cast.

Flying
Whenever an artifact enters the battlefield under your control, you may activate one of its activated abilities without paying its cost.

Flying
Whenever Searshot Dragon deals combat damage to a player, it deals that much damage to target creature that player controls.
{1}{R}: Searshot Dragon gets +1/+0 until end of turn.

Seaside Skimmer can't be blocked if you've cast a Dragon spell or Adventure spell this turn.

Flash
Menagerie — When Seven Seas Scourge enters the battlefield, if there are five or more creature types among creatures you control, counter target spell with mana value 4 or less.

Flying
When Sha Long enters the battlefield, each player chooses an artifact they control, then sacrifices the rest. If they don't control an artifact, they may return an artifact card from their graveyard to the battlefield. Repeat this process for creatures, enchantments, and planeswalkers.

Flying, haste
Whenever Shimmering Dragon attacks, for each creature you control, create a tapped and attacking token that's a copy of that creature. Exile the tokens at the beginning of the end step.

Flying
Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast your second spell each turn, draw a card.

Advance {3}{R}{R} (Cast this for {3}{R}{R} to advance it as it enters. {3}{R}{R}: Advance this as a sorcery.)
Flying, haste
Whenever Skiviar Scraplord advances, put a +1/+1 counter on it.

Flying
Death knell — Skullhoarder Dragon gets +2/+0 until end of turn. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

Flying, trample, haste
Whenever a land enters the battlefield under your control or a land is put into your graveyard from the battlefield, Skyscreecher Dragon deals 2 damage to each opponent.

Flying, haste
Whenever you cast an instant or sorcery spell, Sovereign of Old Jidai gets +1/+0 until end of turn.

Flying
Whenever Starborne Hellkite attacks, choose two—
• Starborne Hellkite deals 4 damage to any target.
• Destroy target artifact or land.
• Creatures you control get +2/+0 until end of turn.