msem-instigator

Create a 1/1 white Soldier creature token. Then put a +1/+1 counter on a creature you control.

When Signet Ring enters, scry 1.
{2}, {T}, Sacrifice Signet Ring: Add two mana of different colors.

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 Silence Dissent enters, each player exiles a card from their hand at random until Silence Dissent leaves the battlefield.
{1}{W}: Exile Silence Dissent. Return it to the battlefield under your control at the beginning of your next end step.

Enchant creature
Enchanted creature gets +1/+1 and has hexproof.

Counter target spell unless its controller pays {1} and 3 life.

Mill three cards, then counter target spell unless its controller pays {X}, where X is the greatest mana value among cards milled this way.

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

Enchant creature
When Silent Call enters, draw a card.
Enchanted creature attacks each combat if able.

You gain hexproof until end of turn.
Prevent all damage that would be dealt to you this 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.)

Flying
When Silent Griffin enters, draw three cards, then put two cards from your hand on top of your library.

Silent Hunt deals 3 damage to target creature and you gain 3 life.
Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Target opponent exiles cards from the top of their library until X land cards are exiled, where X is the number of land cards in your graveyard.

Return target creature to its owner's hand. If you controlled that creature, draw a card.

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

Silent Ridge enters tapped.
{T}: Add {B}.
Desertcycling {1}{B} ({1}{B}, Discard this card: Search your library for a Desert card, reveal it, and put it into your hand, then shuffle.)

Return target creature card from your graveyard to your hand.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Non-Avatar creatures can't attack you or planeswalkers you control unless their controller pays {2} for each of those creatures.

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

Flash (You may cast this spell any time you could cast an instant.)
When Silk Crane Adept enters, target creature gains hexproof until end of turn.

Reach

When Silkweaver Matron enters, create a white Aura enchantment token named Spinning Silk attached to target creature. The token has enchant creature and “Whenever enchanted creature attacks, tap target creature defending player controls.”
{1}{W}: Untap target enchanted creature.

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