msem-instigator

Sunwing has flying as long as it's your turn.

When Sunwright Scion enters, put a +1/+1 counter on each other creature you control.
At the beginning of each combat, you may have target creature with a +1/+1 counter on it gain your choice of vigilance, lifelink, or trample until end of turn.

Enchant creature
Enchanted creature gets +3/+3, has trample, and can only attack alone.

Whenever you cast a spell, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Target permanent you control becomes a 2/2 creature with flying in addition to its other types until end of turn.

Target creature gets +2/+0 until end of turn and gains “When this creature dies, return it to the battlefield tapped under its owner's control.”

You can't cast this spell if you've cast another spell this turn.
Add seven mana in any combination of colors. Spend this mana only to cast red spells with mana value 6 or greater without {X} in their mana cost.

As Superset enters, choose two abilities from among flying, first strike, lifelink, prowess, and vigilance.
Each creature you control with exactly one of the chosen abilities has the other chosen ability.

Whenever Supplanter of Realities attacks, proliferate. (You choose any number of permanents and/or players with counters on them, then give each another kind of a counter already there.)
Sacrifice another permanent: Supplanter of Realities gains indestructible until end of turn. Tap it.

Menagerie — When Supply Hauler enters, if there are five or more creature types among creatures you control, you may search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Supply Run costs {2} less to cast if a creature you controlled attacked this turn and wasn't blocked.
Draw two cards.

Equipped creature has vigilance and “{T}: Add one mana of any color.”
Equip {1}

You may sacrifice three Treasures rather than pay this spell's mana cost.
Flying, trample, haste

Each creature with a law counter on it can't attack or block.
{2}{W}, {T}: Remove all law counters from all permanents, then put a law counter on target creature.

Whenever Supreme Mechanothurge or another artifact you control enters, up to one target artifact you control becomes a copy of another target artifact or creature you control, except it's an artifact in addition to its other types.

Creatures you control get +2/+2 and gain trample until end of turn. If you cast this spell from exile, creatures you control get an additional +2/+2 until end of turn.
Prophecy {2}{G}{G} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

When Suraj Militant enters, target creature gets +1/+1 until end of turn.

{2/R}: Suraj Outrider gets +1/+0 until end of turn.

Target creature gets +3/+0 and gains first strike until end of turn.

Identity — Sureshot Recruit has reach as long as you control at least two other creatures that share a creature type with it.

Prowess
Whenever you cast a noncreature spell, Surestrike Elite gains first strike until end of turn.

Haste
Ward—Pay 3 life.
Whenever Surface Expeditioneer attacks, if it's embattled, it deals 2 damage to target player or planeswalker. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

As an additional cost to cast this spell, torment yourself. (You lose 3 life unless you discard a card or sacrifice a nonland permanent.)
Destroy target creature.

Target creature gets +2/+2 and gains trample until end of turn.
Reprise {2}{R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Target creature gets +X/+X until end of turn.
Fabled {X}{R}{R} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

As Surge of the Fellors enters, choose Fellor or Lafterii.
• Fellor — Warriors you control have haste.
• Lafterii — Wizard creatures you control have “{2}{R}, {T}: This creature deals 1 damage to target player or planeswalker.”