msem-instigator

As an additional cost to cast this spell, discard a card.
Draw two cards unless any opponent discards two cards.

Vigilance
Sun's Own has indestructible as long as it's your turn.

Sun-Dappled Paragon enters with a +1/+1 counter on it for each other creature you control.
Whenever another creature you control enters, put a +1/+1 counter on Sun-Dappled Paragon.

Whenever another creature you control enters, Sunblessed Orator deals 1 damage to each opponent and you gain 1 life.

{W}: Target creature gains vigilance until end of turn.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{R}{W}: Creatures you control gain flying and haste until end of turn.

Flying
When Sunchaser Mantas enters, choose a color. Look at the top four cards of your library. You may reveal a card of the chosen color from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Equipped creature gets +1/+0 and has “Whenever this creature deals damage to a player or planeswalker, you may draw two cards. If you do, discard a card.”
Equip {2}

Create two 2/2 white Griffin creature tokens with flying. If you control a legendary creature, create three of those tokens instead.

({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}.

Pressure {3}{B}{G} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
When Sunken-Eye Angler enters, mill three cards. Then if it was cast for its pressure cost, you may return a creature card from your graveyard to the battlefield.

Lifelink
When Sunlight Dancer enters, target opponent gains 4 life.

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

When this artifact enters, you gain 3 life. Surveil 2.
{T}: Add one mana of any color.

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

Hexproof
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
As long as Sunrise Sentinel is renowned, other Scouts you control have hexproof.

Sunspear Surge deals 2 damage to target creature and 1 damage to each other creature.

When Sunwright Scion enters, put a +1/+1 counter on each other creature you control.
At the beginning of each combat, you may have target creature with a +1/+1 counter on it gain your choice of vigilance, lifelink, or trample until end of turn.

Each creature with a law counter on it can't attack or block.
{2}{W}, {T}: Remove all law counters from all permanents, then put a law counter on target creature.

When Suraj Militant enters, target creature gets +1/+1 until end of turn.

Menace, reach
When Surfacing Horripede enters, surveil 2.

Target creature gets +X/+X until end of turn.
Fabled {X}{R}{R} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Surging Lightning deals 2 damage to target creature or planeswalker. If you've cast another spell this turn, it deals 4 damage instead.

Submerge up to two target attacking nontoken creatures an opponent controls. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)