msem-instigator

Trample, haste
Whenever Sugon, Destruction's Fist deals combat damage to a player, return it to its owner's hand unless you have Sugon deal 5 damage to you.

Flying
Suisei the Southern Star gets +1/+1 for each comet counter you have.
Whenever you cast an instant or sorcery spell with mana value greater than the number of comet counters you have, you may pay {R}. If you do, return Suisei from your graveyard to the battlefield, then you get a comet counter.

Prowess
Disgraced 2 (This enters with two -1/-1 counters. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)

At the beginning of your upkeep, Suitor of the Sea deals 1 damage to each player.

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
{5}{R}: Sullivan's Courier gets +2/+2 until end of turn.

Haste
Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)

Flying, haste
Assault {1}{R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on a creature you control, you may return Sunnula's Firebird from your graveyard to your hand.

Sunrise Bluffs enters tapped.
{T}: Add {R}.
You may untap Sunrise Bluffs during each other player's untap step. Whenever you do, you lose 1 life.

Sunset Cliffs Hunter gets +1/+0 and has first strike as long as a player controls a permanent with a bounty counter on it.

When Sunset Cliffs Lawman enters, you may post a bounty on target creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

Sunspear Surge deals 2 damage to target creature and 1 damage to each other creature.

{T}, Pay 1 life: Add {R}.
{T}, Pay 1 life, Sacrifice Sunwashed Spires: Search your library for a Mountain card, put it onto the battlefield tapped, then shuffle.

Haste
At the beginning of your end step, return Sunwatcher Aspirant to its owner's hand.

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.

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.

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

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

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.)

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.”

Enchant creature
Enchanted creature has haste and first strike.

Surging Lightning deals 2 damage to target creature or planeswalker. If you've cast another spell this turn, it deals 4 damage instead.

Target creature gains double strike and trample until end of turn. (Then exile this card. You may cast the creature later from exile.)