msem-instigator

Reveal the top four cards of your library. Put up to two creature cards with mana value 3 or less from among them onto the battlefield and the rest into your graveyard.
Prophecy {2}{G} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

Whenever a land you control enters, if you haven't had a land become a copy this way this turn, you may have that land enter as a copy of any nonland permanent on the battlefield.

You may have Sun Yun enter as a copy of any creature on the battlefield, except her name is Sun Yun, Master of Man, she's legendary in addition to her other types, and she has “{2}{U}: Exile Sun Yun, then return her to the battlefield under her owner's control.”

If a creature entering the battlefield under your control causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
{1}{U}, {T}: Exile another target creature. Return it to the battlefield under its owner's control at the beginning of the next end step.

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

When Sun-Blessed Hoplite enters, target creature you control gets +X/+X until end of turn, where X is your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)

{2}: Other creatures you control get +1/+0 until end of turn.
Whenever Sun-Crowned Flagship attacks, each attacking creature you control gains trample until end of turn.
Crew 7 (Tap any number of creatures you control with total power 7 or greater: This Vehicle becomes an artifact creature until end of 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.

Vanguard — Whenever a creature you control attacks alone, you may cast a spell with mana value 3 or less from your hand without paying its mana cost.

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.

You may pay {W}{U}{B}{R}{G} rather than pay this spell's cost.
When Suncolored Dreamer enters, draw a card.

You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost.

When Sundering Arcanist enters, you may destroy target artifact or enchantment.
If you would draw a card, you may sacrifice a land and mill four cards instead. If you do, return Sundering Arcanist from your graveyard to your hand.

Whenever a land you control enters or a land card is put into your graveyard from anywhere, create a 0/1 green Plant creature token.
{3}{G}{G}: Put a +1/+1 counter on each other creature you control.

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

Flying
As long as it's your turn, creatures you control get +3/+0 and have vigilance.
As long as it's not your turn, creatures you control get +0/+3 and have lifelink.

Primal {1}{W}{W} (During your turn, you may cast this spell for {1}{W}{W} instead of playing a land.)
Double strike
When Sunken Slasher enters, if you didn't play a land this turn, put a +1/+1 counter on it.

You gain life equal to the number of creatures you control.
Each opponent loses life equal to the number of creatures they control.
Destroy all creatures, then exile all graveyards.

Haste
Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)

Flying, haste
Assault {1}{R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on a creature you control, you may return Sunnula's Firebird from your graveyard to your hand.

Equipped creature has “{T}: This creature deals damage equal to its power to any target.”
Equip {4}

When Sunset Cliffs Lawman enters, you may post a bounty on target creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)