msem-instigator

Menace, reach
When Surfacing Horripede enters, surveil 2.

As an additional cost to cast this spell, torment yourself. (You lose 3 life unless you discard a card or sacrifice a nonland permanent.)
Destroy target creature.

Target creature gets +2/+2 and gains trample until end of turn.
Reprise {2}{R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

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.)

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.

Whenever equipped creature attacks, choose one —
• Tap target creature.
• Draw a card, then discard a card.
• Exile target card from a graveyard.
Equip {3}

When Suspect Concoctions enters, put a +1/+1 counter on target creature.
{4}, Sacrifice Suspect Concoctions: Put two +1/+1 counters on target creature.

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

When this creature enters, target creature you control gets +1/+1 and gains vigilance until end of turn. You may remove a counter from that creature.

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.