msem-instigator

Lifelink
When Stalked Healer enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Bloodprice {2}{U} (You may cast this card by sacrificing a creature and paying its bloodprice.)

When Stalwart Physicker enters, you may remove a -1/-1 counter from target creature.

Trample
Other creatures you control with trample get +2/+2.
{4}{R}{G}: Put a trample counter on target creature.

Trample, ward {1}
Whenever Stardust Surveyor deals combat damage to a player, you may mill cards until you mill a creature card. When you do, return target creature card from your graveyard to your hand.

{G}, Discard a card: Staunch Constrictor gets +1/+1 until end of turn.

Steel Hunter can't attack unless you control three or more other artifacts.

Steelborn Apprentice gets +1/+1 as long as you control an Equipment.

Flash
Advance {3}{W} (Cast this for {3}{W} to advance it as it enters. {3}{W}: Advance this as a sorcery.)
Whenever Steelwoven Soldier advances, it gets +2/+2 until end of turn.

When Steward of Empire's Cradle enters, you may search your library for a Discovery, Quest, or Saga card, reveal it, then shuffle and put that card on top.
Civilized — If an ability of an enchantment you control triggers, if you control an artifact, a creature and an enchantment, that ability triggers an additional time.

{1}, {T}: Tap target creature with the greatest power among creatures your opponents control.

Still-Smoke Hunter gets +2/+1 and is a Beast in addition to its other types while it's tapped.
Revive {3}{B} ({3}{B}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

{2}{G}: Look at the top three cards of your library. You may reveal a creature or Revelation card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

When Still-Smoke Sojourners enters, remove all counters from target player or permanent. That player or that permanent's controller loses life equal to the number of counters removed this way.

If you would draw a card, you may skip that draw. If you do, create a tapped Treasure token and exile the top card of your library. You may play that card this turn.

Deathtouch
Menagerie — When Sting-Hopper enters, if there are five or more creature types among creatures you control, target player reveals their hand. You choose a creature card from it. That player discards that card.

Deathtouch

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Whenever you cast a spell that doesn't share a color with Stinging Hunter, each opponent loses 1 life.

Reach
Stonebark Incinerator gets +2/+0 and has trample as long as you control a Dwarf.
Stonebark Incinerator gets +0/+2 and has vigilance as long as you control a Elf.

When Stonefall Golem leaves the battlefield, destroy target permanent.

Whenever Stonehoof Familiar is dealt damage, put a +1/+1 counter on it. (It must survive the damage to get the counter.)
Menagerie — As long as there are five or more creature types among creatures you control, all damage that would be dealt to you or other permanents you control is dealt to Stonehoof Familiar instead.

Improve {1} ({1}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
{3}{W}: Return target nonland permanent card with mana value 1 or less from your graveyard to your hand. This ability cost {1} less to activate for each counter on Stoneport Provisioner.

At the beginning of your upkeep, if Stonework Infantry is on the battlefield, each player returns all cards named Stonework Infantry from their graveyard to the battlefield.

Flying
Stormcloud Drake gets +1/+0 for each instant and sorcery card in your graveyard.
Whenever Stormcloud Drake attacks, tap target creature defending player controls.