msem-instigator

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.)

{T}, Pay 1 life: Add {G}.
{8}{G}, Exile Singers' Grove from your hand: Creatures you control get +7/+7 until end of turn.

{T}, Sacrifice Skeletal Oasis: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Sky-High Spires enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Skylight Fortress enters tapped.
When Skylight Fortress enters, you may search your library for a card named Skylight Fortress, reveal it, put it into your hand, then shuffle.
{T}: Add {C}.

At the beginning of combat on your turn, target creature you control with flying gets +1/+1 until end of turn.

Slipsand Oasis enters tapped unless you played it from exile.
{T}: Add {W} or {B}.

Slipstream Horizon enters tapped.
{T}: Add {U} or {R}.
{U}{R}, {T}, Sacrifice Slipstream Horizon: Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

(Transform this if it's not attached to a creature. Pay {2}{W} as a sorcery to unattach it.)
Enchant creature you control
Slopestrider's Chariot's rider gets +1/+1 and has double strike.

{T}: Add {C}.
{4}, {T}, Sacrifice Slyten Crystal Motherlode: Add {W}{U}{B}{R}{G}.

{T}: Add {C}.
{T}: Add one mana of any color. You can't spend this to cast spells from your hand.

Snow Drift enters tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {U}.
{4}{U}: Snow Drift becomes an Elemental creature. (This effect lasts indefinitely.)

{T}: Add {C}.
{T}, Pay 1 life: Add {R} or {W}.

{T}: Add {C}. If Soaring Observatory entered this turn, add one mana of any color instead.
Tap three differently named untapped Academies you control: Add three mana in any combination of colors.

({T}: Add {G} or {U}.)
Soaring Rainforest enters tapped.
{1}, {T}: Add {G}{G} or {U}{U}.

({T}: Add {U} or {B}.)
Sodden Cavern enters tapped.

Sodden Path enters tapped unless you control one or fewer other lands.
{T}: Add {G} or {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Lifelink
When you attain Sojourner of the Beyond, create two 1/1 white Spirit creature tokens with flying. They gain haste until end of turn.

{T}: Add {C}.
Satrapies you control have “{1}{W}, {T}, Exile a card from your graveyard: Create a 1/1 white Soldier creature token.”

Soli Sanctuary enters tapped.
Satrapies you control have “{T}: Add {W} or {U}.”

Soli Temple enters tapped.
Satrapies you control have “{T}: Add {G} or {W}.”

({T}: Add {B} or {G}.)
Somber Marsh enters tapped.

Somber Meadow enters tapped.
{T}: Add {W} or {B}.
{1}, {T}: Add one mana of any color.