msem-instigator

Enchant creature
Enchanted creature has haste and first strike.

Whenever a creature you control becomes the target of a spell, that creature gets +3/+3 until end of turn.

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.)

You may have Surging Wurm assign its combat damage as though it weren't blocked.
Surging Wurm gets +2/+2 as long as seven or more cards are in your graveyard.

Target creature gains double strike and trample until end of turn. (Then exile this card. You may cast the creature later from exile.)

Until end of turn, target creature gets +1/+1 and gains lifelink.

Flash
When Surreal Bakhtak enters, choose one —
• Destroy target tapped creature.
• Tap up to three target creatures.

Flying, prowess
Whenever Surveyor of Skies attacks, you may return a permanent you control to its owner's hand.

When Surveyor's Rifle enters, rediscover a land card. (Look at the top card of your library. You may reveal it and put it into your hand if it's a land card. Otherwise, put it back or into your graveyard.)
Equipped creature gets +2/+1.
Equip {3}

Wanderlust — When you cast this spell, you may copy it if you control four or more differently named lands. You may choose new targets for the copy.
Untap target creature you control. It gets +1/+1 and gains hexproof and indestructible until end of turn.

Regenerate target creature. (The next time that permanent would be destroyed this turn, it isn't. Instead tap it.)

Return up to one target creature card and up to one target land card from your graveyard to your hand.

Prowess
When Surviving Scavengers enters, you may draw a card, then discard a card.

When Suspect Concoctions enters, put a +1/+1 counter on target creature.
{4}, Sacrifice Suspect Concoctions: Put two +1/+1 counters on target creature. (A suspected creature has menace and can't block.)

Enchant land
Enchanted land has “{W}, {T}: You gain 2 life.”

As an additional cost to cast this spell, discard a card.
Return up to one target instant card and up to one target sorcery card from your graveyard to your hand. Exile Sustaining Meditation.

Each other Rogue creature you control enters with an additional +1/+1 counter on it.
Remove a +1/+1 counter from a creature you control: That creature can't be blocked this turn.

Swallowed by the Earth deals 4 damage to target creature. Destroy all Equipment attached to that creature.

Swarm of Sporemites gets +1/+1 for each creature card and Revelation card in your graveyard.

Target creature deals damage equal to its power to its controller.

{T}: Add {C}.
{T}, Pay 1 life: Add {W}.
{5}{W}, {T}, Sacrifice Swaying Sands: Create three 1/1 white Bird creature tokens with flying. Activate only as a sorcery.

Flying
When Sweeper Drone enters, create a Function token with “Put a +1/+1 counter on each creature named Sweeper Drone you control.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

You may tap two untapped red creatures and/or planeswalkers you control with different names rather than pay this spell's mana cost.
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.