msem-instigator

Haste
Ward—Pay 3 life.
Whenever Surface Expeditioneer attacks, if it's embattled, it deals 2 damage to target player or planeswalker. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Menace, reach
When Surfacing Horripede enters, surveil 2.

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.)

As Surge of the Fellors enters, choose Fellor or Lafterii.
• Fellor — Warriors you control have haste.
• Lafterii — Wizard creatures you control have “{2}{R}, {T}: This creature deals 1 damage to target player or planeswalker.”

Search your library for a basic land card and put it onto the battlefield, then shuffle.
Orchestrate {1}{G} (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)

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.

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.)

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}

Spells you cast have trial 2. (As you cast them, an opponent of your choice may pay 2 life. If they don't, they fail the trial.)
Whenever an opponent fails a trial of a creature spell, that creature enters with an additional +1/+1 counter on it.
Whenever an opponent fails a trial of a noncreature spell, create a tapped Treasure token.

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.

Haste
{T}, Discard a card: Flip a coin. If you win the flip, draw two cards. Otherwise, you may pay {R}. If you do, repeat this process.

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.

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.

Swarming Midden enters tapped unless you control a basic Swamp.
{T}: Add {B}.
{1}{B}{B}: Swarming Midden becomes a 2/3 black Rat creature with menace until end of turn. It's still a land. Whenever it attacks this turn, create a 1/1 black Rat creature token with “This creature can't block.”

{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.

At the beginning of combat, each player chooses a creature. Those creatures attack or block this turn if able. Whenever one of those creatures dies this turn, Sweep Stakes deals 3 damage to that creature's controller.

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.)