msem-instigator

Whenever a Survivor you control dies, you draw a card and you lose 1 life.

{3}: Sellsword Contraption becomes the creature type of your choice until end of turn.

When Seluriel's Blessing enters, put a +1/+1 counter on each creature you control.
Creatures you control enter with an additional +1/+1 counter on them.
Creatures you control with counters on them have vigilance and indestructible.

[+1]: You gain 1 life. Put a +1/+1 counter on up to one target creature.
[–3]: Exile target creature. Its controller gains life equal to its power.
[–8]: You get an emblem with “Creatures you control get +1/+1 and have double strike and lifelink.”

When you cast Senaturian Centurion, reveal cards from the top of your library until you reveal a creature card with mana value 2 or less. Copy that card, then put the revealed card into your hand. You may cast the copy without paying its mana cost. Put the revealed cards on the bottom of your library in a random order.

When Sending Stones enters, harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)
If you would harmonize, you may trigger a harmony of a permanent card in your graveyard instead.

Destroy target creature. Trigger a death knell of a permanent you control.

Death knell — Put a +1/+1, flying, lifelink, or menace counter on Senn, the Haunting Gaze, then trigger a death knell of another permanent you control. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

When Sensational Festivities enters or at the beginning of your upkeep, you may draw a card. If you do, each opponent may draw a card, then discard a card.

Target player discards two cards. If a creature you control died this turn, that player loses 2 life.

Untap all permanents you control during each other player's untap step.

{2/U}, {T}: Target creature gets -4/-0 until end of turn.

When Sentient Contraption enters, create a 1/1 colorless Thopter artifact creature token with flying.

Lionize {1}{W} ({1}{W}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Flying

Soldiercycling {1}{W}, Wizardcycling {1}{U}, Zombiecycling {1}{B}, Warriorcycling {1}{R}, Elfcycling {1}{G} ({1}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)
Sentinel of Latter Days is every creature type as long as it's in your library.

Sentinel of the Highlands has hexproof as long as it's embattled. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Equipped creature gets +2/+0. As long as it's a Knight, it has first strike.
Equip {1}{W}

Whenever Sentry of Kollis Gate is dealt damage, put a +1/+1 counter on each other creature you control.

Deathtouch, menace
As long as you control another Knight creature, Ser Joffrey, Plague of Nines and other Knight creatures you control have first strike.

Whenever Ser Wayver, the Broken Hour attacks, each opponent loses 2 life and you gain that much life.
When Ser Wayver dies or is countered, exile it with three time counters on it and it gains suspend. (At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast this card without paying its mana cost. It has haste.)

Deathtouch
{U/B}: Change a target of target spell or ability that targets Serafina to another creature you control.
Whenever Serafina deals damage to a player, at the beginning of the next end step, that player loses life equal to the life they lost this turn.

Flying
When Seraph of Renewal leaves the battlefield, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Flying, vigilance, lifelink
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Flying
Whenever you cycle Seraph of the Stage or it attacks, audition for white. (Create a 1/1 Construct Actor creature token, a Scout Role giving 2/3 and vigilance, or a Cleric Role giving 2/2 and lifelink. Roles replace older ones.)
Basic landcycling {1}{W} ({1}{W}, Discard this card: Search your library for a basic land card, reveal it, and put it into your hand, then shuffle.)

Draw two cards. If you control an Angel, draw three cards instead.