msem-instigator

Flying
Whenever you cast your first spell each turn, add {U}{U}, {U}{R}, or {R}{R}.
Whenever you cast your second spell each turn, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Whenever you cast your third spell each turn, Stirring Igmel deals 3 damage to each opponent.

Create a 2/2 red and white Cat Knight creature token. Creatures you control get +1/+1 and gain haste until end of turn.

Whenever you cast a creature spell, you may return target nontoken creature you control with a different name to its owner's hand. If you do, copy that spell. (A copy of a creature spell becomes a token.)

Target creature you control gains indestructible until end of turn. Whenever that creature perseveres this turn, create a 2/2 black Zombie creature token. (A creature perseveres when it survives damage.)

You may cast spells from among cards you put into your graveyard from your library this turn.
Whenever one or more cards leave your graveyard, create a tapped 2/2 black Zombie creature token.
When Stitched Gargantua is put into your graveyard from your library, you may return it to your hand.

When Stolen Innovations enters, target opponent reveals their hand. You choose an instant or sorcery card from that player's hand or graveyard and exile it.
You may cast each spell you cast from your hand as a copy of the exiled card. You may spend mana as though it were mana of any color to cast spells this way.

When Stolen Light enters, exile target nonland permanent an opponent controls until Stolen Light leaves the battlefield.
{W}{U}{B}{R}{G}: Put a permanent card exiled with Stolen Light onto the battlefield under your control. It's a 3/3 Horror creature in addition to its other types.

Take an extra turn after this one. At the beginning of that turn's upkeep, if you control a legendary creature, each opponent exiles the top card of their library. Until the end of that turn, you may play those cards and you may spend mana as though it were mana of any type to cast those spells.
Exile Stolen Moments.

Trample

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.

Reach
Whenever this creature attacks, target creature with power less than or equal to the number of creatures you control can't block this turn.
{3}{G}: Attacking creatures get +1/+0 and gain trample until end of turn.

Flying
Tap an artifact you control, a creature you control, and an enchantment you control: Return Stonecut Lammasu from your graveyard to your hand. Activate only as a sorcery.

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.

Destroy target artifact or nonbasic land.

Whenever you cast a spell, if it isn't your main phase, you may have Stoneshrine Guardian's base power and toughness become 4/1 or 1/4 until end of turn.

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +2/+2.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Renown 3 (When this creature deals combat damage to a player, if it isn't renowned, put three +1/+1 counters on it and it becomes renowned.)

Stonework Idol's power and toughness are each equal to the number of creatures you control.

Destroy target artifact or nonbasic land. Its controller creates a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

This spell costs {2} less to cast if you control a legendary creature.
Search your library for a creature or land card, reveal it, put it into your hand, then shuffle.

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

Until end of turn, creatures target player controls lose all abilities and have base power and toughness 0/2.
Inscribe {4}{B}{B} ({4}{B}{B}: 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.)

You may pay {1}{R}{R} and tap an untapped Knight you control rather than pay this spell's mana cost.
Target untapped creature you don't control blocks this turn if able. Other creatures can't block this turn.