msem-instigator

Flash
Whenever you cast Siflir, Elder Pawn or another spell, if you paid an alternate or additional cost to cast it, draw a card.
Wander {3}{U}{U} (You may cast this from the battlefield for its wander cost.)

When Sihari's Groundblazer enters, create a red Aura enchantment token named Searing Crags attached to target land. The token has enchant land, “Enchanted land's name is Charred Causeway” and “Enchanted land has {T}: This land deals 1 damage to each opponent.”

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

Silent Doom enters tapped.
You may cast Silent Doom from your graveyard as long as you sacrificed a permanent this turn.
Cycling {B} ({B}, Discard this card: Draw a card.)

Prevent all combat damage that would be dealt to Silent Reaver.
Prevent all combat damage Silent Reaver would deal to creatures.

Flash
You may cast cryptic spells as though they had flash. (Artifacts, enchantments, and modal spells are cryptic.)

{2}, Pay 2 life: Silkwrap Brawler gains indestructible until end of turn.

Whenever Silt Lurker deals combat damage to a player, mill three cards, then draw a card if seven or more cards are in your graveyard.
Cycling {G} ({G}, Discard this card: Draw a card.)

When Silt Miner enters, you may salvage an artifact or creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

{T}: Untap another target nonland permanent. Activate only as a sorcery.

Silver-Dawn Elder gets +2/+2 as long as you control five or more lands.
Revive—{2}{G}{G}, Discard a card. ({2}{G}{G}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

Menace
Whenever Silver-Dawn Radiant becomes the target of a spell or ability you don't control, it deals damage equal to its power to that spell or ability's controller.

Trample
Whenever Silver-Dawn Ranger becomes the target of a spell, put a +1/+1 counter on each Warrior you control.

When Silvercrest Historian enters, scry 1, then investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

When Silverhorn Battlemaster enters, put a +1/+1 counter on up to two target Warriors you control.
Whenever Silverhorn Battlemaster deals combat damage to a player, permutate. (You may remove a counter from a creature you control. If you do, put two +1/+1 counters on a different creature you control.)

Whenever Simian Striker attacks, it gets +3/+0 until end of turn.

As long as you are glorious, you may look at the top card of your library. (You are glorious as long as you have a glory counter.)

Flying
Whenever Sinewed Wings deals combat damage to a player, you may discard your hand. If you do, draw a card for each creature with flying you control.

Whenever you attack, each opponent loses 3 life unless they discard a card or sacrifice a nonland permanent. Repeat this process once.
Fleeting {B}{R} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Whenever Single-Minded Mob becomes untapped, it gets +2/+2 until end of turn.

Whenever a storied permanent you control enters, each opponent loses 1 life and you gain 1 life. (Enchantments and legendary permanents are storied.)
{2}{B}{B}, Sacrifice Sinister Heir: Return target storied card from your graveyard to the battlefield.

Death knell — You gain 2 life. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

Haste
Sixpod Sprinter can't be blocked except by creatures with flying or reach.

When Skeletal Shredwing enters, target creature can't block this turn.
Revive {5}{R} ({5}{R}, 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.)

Whenever an embattled creature you control dies, you may return Skhorvall Eternal from your graveyard to your hand. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)