msem-instigator

Vigilance
When Scion of Storms enters, create a 2/2 white Elemental creature token with flying.
Whenever a Plains you control enters, you may aetherize Scion of Storms. (To aetherize, create a token that's a copy of it, then exile that token.)

At the beginning of your upkeep, if six or more cards are in your graveyard, you may transform Scuttling Gnat.

Sea Of Skies Beyond enters tapped.
Whenever you cast a noncreature spell, put a creation counter on Sea Of Skies Beyond.
{T}, Remove ten creation counters from Sea Of Skies Beyond and sacrifice it: Shuffle your hand into your library, then draw five cards.

Concord — {1}{G}: Until end of turn, Seadrake Rider gets +2/+3 and must be blocked if able. Activate only during your turn, only once each turn, and only if there are four or more card types among permanents you control.

Flash
{U}, Sacrifice Seal of Approval: Counter target spell unless its controller pays {2}.

Target permanent you control deals 2 damage to any target.
Inscribe {2}{R}{R} ({2}{R}{R}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Instant and sorcery spells you cast cost {1} less to cast.
Rapport — Whenever Selma Lappowen and at least one other creature you control become tapped, exile the top card of your library. Until end of turn, you may play that card.

Equipped creature gets +1/+1 and has deathtouch.
{1}: Serpent Staff becomes a 1/1 green Snake creature with deathtouch and loses all other abilities until end of turn.
Equip {3}

[+1]: You may sacrifice a permanent. If you do, each opponent sacrifices a permanent that shares a type with it.
[–2]: Put target creature card in a graveyard onto the battlefield under your control.
[–8]: You control target player during their next turn. During that turn, that player may cast spells by paying life equal to their mana value rather than pay their mana cost. After that turn, that player takes an extra turn.

As long as it's your turn, Seto San is a 3/3 Human Warrior creature with indestructible.
[+1]: Up to one target creature you control gains lifelink until end of turn.
[0]: Create a 1/1 white Warrior creature token.
[–X]: Search your library for an Aura or Equipment card with mana value X and put it onto the battlefield, then shuffle.

[+1]: Create two 1/1 white Warrior creature tokens. You gain 2 life.
[–2]: Destroy each creature with the greatest power or tied for the greatest power among creatures on the battlefield.
[–5]: Creatures you control get +X/+X and gain lifelink until end of turn, where X is the number of creatures you control.

Destroy all creatures.

Shadowband Consul enters tapped.
{B}, Pay 2 life: Return Shadowband Consul from your graveyard to the battlefield. Activate only if an opponent lost life this turn.

Pressure {2}{G}{G} (You may cast this spell for its pressure cost if there are seven or more cards in your graveyard.)
Trample, hexproof
Shambling Dreadreef's power and toughness are each equal to the total number of land cards you own on the battlefield and in your graveyard.

Flying, haste
Whenever Shimmering Dragon attacks, for each creature you control, create a tapped and attacking token that's a copy of that creature. Exile the tokens at the beginning of the end step.

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.)
Sacrifice a creature: Shinrei of the Ghosting Way can't be blocked this turn.
Whenever one or more Rogues you control deal combat damage to a player, return a creature card from your graveyard to your hand.

Deathtouch
When Siesa Tremund enters, for each player, search that player's library for a card and exile it. That player shuffles. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any type to cast those spells.

When Sights Beyond enters, scry 3.
Concord — At the beginning of your upkeep, if there are four or more card types among permanents you control, draw a card.

Flying
Sire of Empires gets +1/+1 as long as you control another creature, has lifelink as long as you control an enchantment, and has vigilance as long as you control an artifact.

When Sire of the Wild enters, reveal the top four cards of your library. You may put a creature card from among them onto the battlefield. Shuffle the rest into your library.

Haste
Whenever a creature attacks, Slashing Pangolin gets +1/+1 until end of turn.

Slaughterkeg can't attack or block.
While an opponent is choosing targets as part of casting a spell they control or activating an ability they control, that player must choose at least Slaughterkeg if able.
When Slaughterkeg dies, draw a card.

Enchant land
Whenever enchanted land is tapped for mana, its controller adds {G}.
{G}, Sacrifice Sleeping Dryads: Draw a card.

When Snagged Truck enters, investigate three times. (Create three colorless Clue artifact tokens with “{2}, Sacrifice this: Draw a card.”)
Snagged Truck can't attack or block as long as you control a Clue.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)