msem-instigator

Stoic Djinn has flying as long as it has a counter on it.

Double strike, vigilance, lifelink

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.

Haste
Storm Entity enters with a +1/+1 counter on it for each other spell cast this turn.

Whenever a permanent you control becomes tapped, Storm Servant gets +1/+1 until end of turn.

Stormbred Elemental gets +1/+1 as long as you control an Island.
{U}: Stormbred Elemental gains flying until end of turn.

Prowess, haste

Whenever one or more creatures you control deal combat damage to a player, exile a nonland card from that player's graveyard. Copy it. You may cast the copy. (You still pay its costs, including color. Copies of permanents enter as tokens.)

{1}, {T}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
{2}, {T}, Exile an instant or sorcery card from your graveyard: Stormvolt Apprentice deals 1 damage to each opponent.

Flash
Flying
When Strange Sights dies, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Prowess
Pay 2 life: Change a target of target spell or ability to Straw Intellectual.

Stray Sighthound can't be blocked by creatures with power 2 or less.
Attain {3}{G} ({3}{G}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

When Street Stalker enters, target opponent loses 1 life for each creature you control named Street Stalker.

Whenever you make first contact, target creature you control can't be blocked by Humans this turn. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Harmony — Target creature gains haste until end of turn.
When Streetside Entertainer enters, harmonize. (Trigger up to one harmony of one permanent you control.)

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.)
At the beginning of combat on your turn, target creature you control with mana value 3 or less can't be blocked this turn. If Streetwise Investigator has two or more counters on it, that creature gains vigilance until end of turn.

Whenever Strict Instructor attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Tap or untap another target permanent.

Whenever you cast a spell, if it isn't your main phase, scry 1.

Flying
Whenever you cast a noncreature spell, note its mana value.
When Strix of Dark Omens dies, draw a card and create a 1/1 blue Bird creature token with flying for each different number noted with it.

Whenever another Warrior creature you control attacks, you may return Stubborn Blademate from your graveyard to the battlefield tapped and attacking. If you do, sacrifice it at end of combat.

{T}: Target creature you control gets +1/+1 until end of turn. Activate only as a sorcery.
Scavenge {W} ({W}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Once each turn, when you discard a card, you may draw a card.
{1}, Discard a card: Substack Smuggler can't be blocked until end of turn.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
At the beginning of your end step, Substack Sniper deals 1 damage to you and to each cursed opponent.

Lifelink

At the beginning of your upkeep, Suitor of the Sea deals 1 damage to each player.