msem-instigator

(Transform this if it's not attached to a creature. Pay {2}{W} as a sorcery to unattach it.)
Enchant creature you control
Slopestrider's Chariot's rider gets +1/+1 and has double strike.

Equipped creature gets +2/+1.
Whenever equipped creature blocks or becomes blocked by a creature, it deals 2 damage to that creature.
Equip {2}

When Smuggler of the Santriza enters, you may discard a card. If you do, draw a card.

Equipped creature gets +1/+1.
Whenever equipped creature attacks, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Equip {2}

Flying

When Sofia's Swashbucklers enters, you may return target card with foretell from your graveyard to your hand.

Foretell {B}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Haste
Whenever Sofia deals combat damage to an opponent, exile the top card of that player's library face down and look at it. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any type to cast that spell. Then foretell Sofia. It costs {0} to foretell this way.

Target opponent separates all creatures into two piles. You choose one of those piles. For each creature in the chosen pile, its controller sacrifices it.

Destroy target artifact or enchantment. You gain 4 life.

Target player discards two cards.

Mimic—Discard a card (Discard a card as a sorcery: This takes the shape of your choice.) [1/1]
[Shape 1] Menace
Soulshifter gets +1/+1 for each creature card in your graveyard. [1/1]
[Shape 2] Deathtouch
Whenever Soulshifter deals combat damage to a player, you may return target creature card from your graveyard to your hand. [2/2]

Whenever Sower of Sabne's Harvest enters or attacks, align X, where X is your fealty to Forests. (Choose modes with total ★ less than or equal to the number of Forests you control. You may choose modes multiple times.)
• ★★ — Put a +1/+1 counter on target creature.
• ★★★ — Exile target artifact or enchantment.
• ★★★★★ — You gain 5 life.

Sparring Ground enters with a +1/+1 counter on it.
{T}: Add {C}.
Whenever a creature you control enters, you may move a +1/+1 counter from Sparring Ground onto that creature.

Menace
Whenever you cast a cryptic spell, you may return target creature card from your graveyard to your hand. (Artifacts, enchantments and modal spells are cryptic.)

Equipped creature gets +3/+3.
Whenever equipped creature attacks, draw a card.
Equip {5}
Equip creature you don't own {0}

Counter target noncreature spell unless its controller pays {2}.

Flying
{2}, Exile an instant or sorcery card from your graveyard: Spellbone Screecher deals 1 damage to any target.

Whenever a land you control enters, target creature gains your choice of flying or lifelink until end of turn.

When Splinter of Creation enters, you may exile any number of land cards from your graveyard.
You may play lands exiled with Splinter of Creation.

Exile target artifact an opponent controls. Until end of turn, you may cast a copy of that card. (You still pay its costs.)

Flying
Whenever you foretell a card or cast a foretold spell, you may scry 1.

This spell costs {1} less to cast if it targets an embattled creature. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)
Put two +1/+1 counters on target creature you control and untap it. It gains hexproof and trample until end of turn.

Flying
Whenever an opponent draws a card except for the first time each turn, create a 1/1 blue Elemental creature token with flying.
Foresight — Whenever you draw your second card each turn, creatures you control get +1/+1 until end of turn.