msem-instigator

Sage's Ashes enters tapped.
{T}, Sacrifice Sage's Ashes: Put target card from a graveyard on top of its owner's library.
{3}, Exile Sage's Ashes from your graveyard: Draw a card.

{T}: Add {C}.
{2}, {T}: Put target Aura or Equipment card from your graveyard on top of your library.

{3}: Create a 9/9 colorless Angel artifact creature token with flying and lifelink.

When Sandswept Bazaar enters, you gain 2 life.
{T}: Add {C}.

{T}: Add {C}.
{5}, {T}, Sacrifice Sandswept Monument: Create a tapped 4/4 colorless Golem artifact creature token.

({T}: Add {U}.)
As Saturated Dunes enters, you may pay 1 life. If you don't, Saturated Dunes enters tapped.

Savage Lands enters tapped.
{T}: Add {B}, {R}, or {G}.

({T}: Add {G}.)
Savage Sanctuary enters tapped with two sanctum counters on it.
{T}, Remove a sanctum counter from Savage Sanctuary: Add {R} or {W}.

Creature spells you cast cost {2} less to cast.
Whenever a creature you control enters, if it doesn't have vanishing, put four time counters on it and it gains vanishing.

Equipped creature gets +1/+1.
Equipped creature has “When this creature dies, if it's not a token, create a token that's a copy of it except it's a colorless Spirit Dragon with flying in addition to its other abilities.”
Equip {2}

When Scanning Module enters, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)
Equipped creature gets +1/+1.
Equip {1}

Scavenger Holdout enters tapped.
When Scavenger Holdout enters, you may pay {3}. If you do, create two 1/1 green Scout creature tokens.
{T}: Add {C}.

When Scintillating Tome enters, choose a nonbasic card name.
{T}: Scry 1, then you may reveal the top card of your library. If a card with the chosen name is revealed this way, put it into your hand.

As Scorched Copse enters, you may tap an untapped creature you control. If you don't, Scorched Copse enters tapped.
{T}: Add {R} or {G}.

Equipped creature gets +2/+2.
{1}: Attach Scoundrel's Aetherlock to target Rogue.
Equip {2}

Scoured Barrens enters tapped.
When Scoured Barrens enters, you gain 1 life.
{T}: Add {W} or {B}.

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

When Scrying Pool enters, scry 2.
{1}, {T}: Add one mana of any color.

Sculpted Observatory enters tapped.
{T}: Add {W} or {U}.
{1}, {T}: Add one mana of any color.

Sea Of Skies Beyond enters tapped.
Whenever you cast a noncreature spell, put a creation counter on Sea Of Skies Beyond.
{T}, Remove ten creation counters from Sea Of Skies Beyond and sacrifice it: Shuffle your hand into your library, then draw five cards.

{T}: Add {C}.
{T}, Tap an untapped artifact, creature, or land you control: Add one mana of any color.
{T}: Choose a card name, then reveal the top card of your library. If that card has the chosen name, you may sacrifice Sealed Archives and draw a card.

Cards in graveyards lose all abilities.
Cards in graveyards can't be the target of spells or abilities.

When Sealed Riftway enters, exile up to one target card from a graveyard.
{2}, {T}, Sacrifice Sealed Riftway: Exile target player's graveyard. Draw a card.

{T}: Add one mana of any color.
{2}, {T}: Draw a card. Activate only if you sacrificed a permanent or discarded a card this turn.

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.