msem-instigator

Shining Showstopper deals 5 damage to any target. Audition for red. (Create a 1/1 Construct Actor creature token, a Warrior Role giving 3/2 and trample, or a Wizard Role giving 2/2 and prowess. Roles replace older ones.)

Whenever you sacrifice a permanent, put a +1/+1 counter on Shipment Overseer.
Surpass {5}{R} ({5}{R}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Shock deals 2 damage to any target.

Equipped creature gets +2/+0.
Equipped creature has first strike as long as it's attacking.
Equip {2}

Shock Blast deals X damage to target creature, where X is the number of instant and sorcery cards in your graveyard.

Shock and Awe deals 2 damage to target creature. Creatures can't block this turn.

Vanguard — Whenever a creature you control attacks alone, Shocking Ewe deals 2 damage to defending player.

Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)
When Shoring Naiad enters, if {U} was spent to cast it, you may return an instant or sorcery card from your graveyard to your hand.

{T}, Sacrifice an artifact: Add {R}{R}{R}.

Haste
Each creature with toughness greater than its power can't block.

Choose one —
• Shredding Blizzard deals 5 damage to target creature.
• Up to three target creatures can't block this turn.

Haste
Whenever you sacrifice another permanent, put a +1/+1 counter on Shrine Razer.

When Siamang Minstrel enters, you may put a lore counter on target Saga you control.

Improve {1}{R} ({1}{R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
When Siegebreaker Ogre enters, create two 1/1 red Goblin creature tokens with haste.

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.”

Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Siltsplitter desecrates a permanent, each opponent sacrifices an artifact.

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.

When Silvershot Crossbow enters, it deals 3 damage to target creature an opponent controls. If that creature is transformed, Silvershot Crossbow deals 13 damage to it instead.
Equipped creature has reach and “{T}: This creature deals 1 damage to each opponent.”
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

First strike

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

Target creature gains trample and haste until end of turn. Harmonize. (Trigger up to one harmony of a permanent you control.)

Haste
At the beginning of combat on your turn, you may have target artifact or enchantment you control become a creature with base power and toughness X/X, where X is its mana value, in addition to its other types and gain haste until end of turn. (If it's attached to a permanent, it becomes unattached.)

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

[+1]: Gain control of up to one target noncreature permanent you don't control until end of turn. Untap it.
[0]: Target player gains control of target permanent you control.
[–7]: You get an emblem with “Whenever you target one or more permanents, gain control of those permanents.”

Double strike
Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
Whenever Sisters Suzakazi attacks, if you control another creature named Sisters Suzakazi, it deals 3 damage to any target.