msem-instigator

Heroic — Whenever you cast a spell that targets Setessan Avenger, create a 1/1 green Nymph Dryad enchantment creature token with “{T}: Add {G}.”
Whenever Setessan Avenger deals combat damage to a player, untap all lands and Dryads you control.

This spell can't be countered.
Flying, protection from cryptic
Whenever you cast a cryptic spell, cast a Sphinx spell, or draw a card, investigate.
{T}, Sacrifice ten Clues: You win the game.

This creature can't be blocked by creatures with power less than the number of creatures you control.
{3}{G}: Create a 1/1 white Peasant creature token.

{2}: Settlement Guardian gets +1/+1 until end of turn for each color of mana spent to activate this ability.

Flash

Flying
When Sha Long enters, each player chooses an artifact they control, then sacrifices the rest. If they don't control an artifact, they may return an artifact card from their graveyard to the battlefield. Repeat this process for creatures, enchantments, and planeswalkers.

Vigilance
Sha'Iv's Emissary gets +1/+1 as long as you control a blue or red permanent.

When Shadow of Izumito dies, choose one —
• Destroy target creature that was dealt damage this turn.
• You may put a progress counter on a Project you control.

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.

When Shadowbinder Touka enters or attacks, exile up to one target creature card from a graveyard.
You may play creature cards exiled with Touka.
Sacrifice another creature: Add two mana in any combination of colors. You can't spend this mana to cast spells from your hand. If this mana is spent to cast a creature spell, that creature enters with a finality counter on it.

Sacrifice Shadowfeeder: Target player loses 1 life and you gain 1 life.

Whenever Shah's Caravan attacks, creatures you control get +1/+1 until end of turn. If you control three or more Satrapies, creatures you control can't be blocked by creatures with power 2 or less this turn.
Satrapycycling {2} ({2}, Discard this card: Search your library for a Satrapy card, reveal it, put it into your hand, then shuffle.)

Whenever a nontoken Satrapy you control enters, create a token that's a copy of it, except it's a 1/1 blue Spirit creature in addition to its other types.
Tap seven untapped Satrapies you control: Exile cards from the top of your library until you exile a nonland card. You may cast that card without paying its mana cost.

When Shaidostan Cryoforger enters, exile the top card of your library.
When Shaidostan Cryoforger dies, you may put the exiled card into your hand.

Haste
Whenever Shala's Phantasm attacks, you may sacrifice a creature. If you do, Shala's Phantasm deals 3 damage to any target.

Trample
While you're searching your library, if Shambling Manglers dealt combat damage to an opponent this turn, you may play lands from your library.

As long as Shambling Morass is on the battlefield or in your graveyard, it's a land in addition to its other types.
When Shambling Morass dies, you may pay {1}. If you do, you draw a card and you lose 1 life.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Whenever a creature enters, its controller sacrifices another creature other than Shan Jun.
{W}{B}: Demigod — Exile each opponent's graveyard. Shan Jun gains protection from each name among cards exiled this way.
{6}{W}{B}: God — Target opponent creates a 1/1 white Avatar creature token with “When this creature dies, you lose the game.”

Trample
Shapen, Spiteful Creation must be blocked each combat if able.
The first time Shapen, Spiteful Creation would be dealt damage each turn, prevent that damage.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Discard a land card: Draw a card. Shardstorm Elemental gets +1/+0 and gains flying until end of turn. Activate only once each turn.

Flash
Unveil {3}{B}{G} ({3}{B}{G}: Transform this. Unveil only as a sorcery.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you casting a noncreature spell causes an ability of a creature you control to trigger, that creature gains your choice of first strike, haste, menace, or trample until end of turn.

As long as it's your turn, Shell Merc has first strike and prowess.