msem-instigator

Equipped creature gets +1/+0 and has menace.
Equip {2}

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

At the beginning of each upkeep, choose one or more —
• Untap target artifact.
• Untap target creature.
• Untap target land.

Equipped creature gets +0/+3 and has menace. (It can't be blocked except by two or more creatures.)
Equip {3}

{T}, Discard your hand: If two or more cards were discarded this way, search your library for a card and put that card into your hand, then shuffle.

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

Equipped creature gets +2/+2.
Whenever equipped creature deals combat damage to a player, you may put a permanent card with mana value 2 or less from your hand onto the battlefield.
Equip {2}

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}.

Equipped creature has “{1}, {T}: This creature deals 1 damage to any target.”
Whenever equipped creature deals damage to a creature with power 5 or greater, sacrifice Sling of the Meek. If you do, destroy that creature.
Equip {3}

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.”)

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

Whenever equipped creature attacks, it gets +3/+3 until end of turn.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

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

At the beginning of your end step, you may put a progress counter on Snowclearer.
[PROGRESS 1-2] Sacrifice Snowclearer: Add {C}.
[PROGRESS 3+] Sacrifice Snowclearer: Add two mana of any one color.

{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.)

{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.