msem-instigator

When you unveil Starlight Guardian, you may put target card from your graveyard on top of your library.
If a card would be put into an opponent's graveyard from anywhere, exile that card instead.

{T}: Add {C}.
{2}, Pay 2 life: Starved Oasis becomes a 4/2 Elemental creature until end of turn. It's still a land.

({T}: Add {U} or {R}.)
Steamlit Peaks enters tapped.
{1}, {T}: Add {U}{U} or {R}{R}.

(Transform this if it's not attached to a creature. Pay {2}{U} as a sorcery to unattach it.)
Enchant creature you control
Steed of the Loch's rider gets +2/+1.
Whenever Steed of the Loch's rider attacks, you may tap target creature an opponent controls.

({T}: Add {W} or {U}.)
Still Waters enters tapped unless you control two or more basic lands.

{T}: Add {C}.
{T}, Exile two cards from your graveyard: Add {U} or {R}.

Stormcharged Pyre enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Strange Harbor enters tapped unless you have 15 or less life.
{T}: Add {U} or {R}.

Stunning Cascade enters tapped.
{T}: Add {U} or {R}.
{2}{U}{R}, {T}, Sacrifice Stunning Cascade: Draw a card.

As Sturdy Outpost enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {G}, {W}, or {U}.

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

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

[+1]: Each opponent loses 1 life for each card you've drawn this turn. Then you draw a card.
[–2]: Sun King's Shadow deals 2 damage to target creature or planeswalker and you gain 2 life. If that permanent was already dealt damage this turn, destroy it.

Sundappled Scrub enters tapped unless you control another Desert.
{T}: Add {G} or {W}.

As Sunflower Fields enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {R}, {G}, or {W}.

({T}: Add {G} or {W}.)
Sungrace Meadows enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Sunken Cavern enters tapped unless another player controls a land that could produce {U} or {R}.
{T}: Add {U} or {R}.

Sunken Homestead enters tapped.
{T}: Add {B}.
{2}{B}: Until end of turn, Sunken Homestead becomes a 2/2 Zombie creature with “When this creature dies, return it to the battlefield.” Activate only if you're horrific.

As Sunless Ridge enters, you may tap an untapped creature you control. If you don't, Sunless Ridge enters tapped.
{T}: Add {B} or {R}.

Sunlit Fissure enters tapped.
{T}: Add {G} or {W}.
{2}{G}{W}: Until end of turn, Sunlit Fissure becomes a 3/5 green and white Elemental creature with with vigilance and “Whenever this creature attacks or blocks, torment yourself.” It's still a land. (To torment yourself, lose 3 life unless you discard a card or sacrifice a nonland permanent.)

As Sunlit Highland enters, you may pay 2 life. If you don't, Sunlit Highland enters tapped.
{T}, Sacrifice Sunlit Highland: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

({T}: Add {W}.)
As Sunlit Meadow enters, you may pay 1 life. If you don't, Sunlit Meadow enters tapped.
Basic lands you control have “{T}: Add {W}.”

({T}: Add {G} or {W}.)
As Sunlit Plaza enters, you may pay {1}. If you don't, Sunlit Plaza enters tapped.

Sunlit Ruins enters tapped unless you control a Swamp.
{T}: Add {G} or {W}.

Sunny Dunes enters tapped unless another player controls a land that could produce {R} or {W}.
{T}: Add {R} or {W}.