msem-instigator

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Abhorrent Exhumer enters, if it engorged a creature card, you may return target creature card from your graveyard to your hand.

Improve {W} ({W}: 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.)
Whenever Frontier Wayfinder attacks, untap each other creature you control.

When Scrivener of Sha'Iv enters, draw a card and adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)

Non-Actor creatures can't block this turn.

Haste
LH-6 Brutality can't attack or block unless you have two or fewer cards in hand.
{T}: Each player discards a card. Activate only as a sorcery.

As long as your deck contains only black and colorless cards, your minimum deck size is reduced by eight.

Target creature gets +2/+1 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Create a Treasure token.
Showcase {2}{R} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Enchant opponent
At the beginning of enchanted player's end step, they discard a card.

Whenever Pelaski Valiant becomes tapped, target creature gets +1/+1 until end of turn.

When Commander of the Cavalry enters, you may search your library for a creature card with ride, reveal it, and put it into your hand. If you do, shuffle.
{X}, {T}: Put a creature card with ride and mana value X or less from your hand onto the battlefield transformed and attached to another target creature you control without a Steed attached to it.

Improve {G} ({G}: 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.)
Whenever an Elf you control dies, you may search your library for a land card, reveal it, put it into your hand, then shuffle.

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

When Prod the Stitchwork enters, it deals 1 damage to target player. That player sacrifices a creature.
At the beginning of your end step, if an opponent was dealt damage by three or more sources this turn, exile the top card of your library. You may play it until the end of your next turn.

Haste
At the beginning of your end step, return Sunwatcher Aspirant to its owner's hand.

This spell costs {1} less to cast for each card type among cards in your graveyard.
Scavenge {4}{G}. This ability costs {1} less to activate for each card type among other cards in your graveyard. ({4}{G}, 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.)

Tears of Samang deals 3 damage to each creature and each player. If an opponent would be dealt damage this way, you may have Tears of Samang deal 3 damage to a planeswalker they control instead.

Creatures your opponents control get -4/-0 until end of turn.
Quickdraw {1}{U}{U} (When a creature you control blocks or becomes blocked, you may cast this spell for {1}{U}{U}.)

You may exert Awoken Elemental as it attacks. When you do, Awoken Elemental fights another target creature. (An exerted creature won't untap during your next untap step.)

Flying
Improve—{1}{B/R}, Sacrifice a creature. ({1}{B/R}, Sacrifice a creature: 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.)
Whenever another creature you control dies, each opponent loses 1 life and you gain 1 life. If that creature was sacrificed, instead each opponent loses 2 life and you gain 2 life.

Equipped creature gets +1/+1.
As long as equipped creature is a Warrior, it has first strike.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

When Performers of Purpose enters, if a permanent you controlled left the battlefield this turn, create a 1/1 colorless Construct Actor creature token.
As long as it's your turn, Performers of Purpose has first strike.

This spell can't be countered.
Flying, menace, haste
Ward—Sacrifice a creature. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player sacrifices a creature.)

When Militant Arms enters, create a 1/1 white Human creature token, then attach Militant Arms to it.
Equipped creature gets +2/+1.
Equip {3}

Flash
Satrapies you control have “{T}: Draw a card.”