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.)

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.”

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.

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.

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}

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.

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.)

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.

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

Deception {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Pay 1 life, Choose a creature card name you haven't chosen for Suzume Oshiruko this turn: Return another creature you control with the chosen name to its owner's hand.

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.

Primal {1}{G}{G} (During your turn, you may cast this spell for {1}{G}{G} instead of playing a land.)
When Swampedge Sentinel dies, return another creature card from your graveyard to your hand.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
Create two 1/1 colorless Construct Actor creature tokens.
Creatures you control gain flying until end of turn. Whenever one or more of them deals combat damage to a player this turn, draw a card.
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Whenever you activate an ability of a card in your graveyard or cast a spell from your graveyard, create a 1/1 blue and black Bird creature token with flying and ward {1}.
Whenever three or more creatures you control deal combat damage to a player, return target creature card with mana value less than or equal to that number of creatures from your graveyard to the battlefield.

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

At the beginning of each end step, create X 1/1 white Spirit creature tokens with flying, where X is the number of nontoken creatures that died this turn.

Flying
At the beginning of your upkeep, you may pay {1}. If you do, put a +1/+1 counter on Swarm of the Dispossessed.
Sacrifice Swarm of the Dispossessed: Counter target spell with mana value X, where X is the number of +1/+1 counters on Swarm of the Dispossessed.

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.