msem-instigator

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.