msem-instigator

You may pay {G}{W} and untap four tapped creatures you control rather than pay this spell's mana cost.
Create four 1/1 green Scout creature tokens.

Target creature gains double strike and trample until end of turn. (Then exile this card. You may cast the creature later from exile.)

{1}, {T}: Tap target artifact, creature, or land.

When Grievous Buccaneer enters, it voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Grievous Buccaneer phases in, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Flying
When Sahra's Harbinger enters, reveal the top six cards of an opponent's library and separate them into two piles. That opponent chooses one of those piles and puts it into their hand. You may cast any number of nonland cards in the other pile without paying their mana costs.

Menace
Whenever CySec Blacksuit deals combat damage to a player or planeswalker, create a Function token with “Choose a nonland card exiled by this spell. For as long as that card is exiled, you may cast it and you mana of any type can be spent to cast that spell.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Target creature you control explores. When it does, it deals damage equal to its power to target creature or planeswalker. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then you may put that card in your graveyard.)

Whenever a player casts a spell, put a time counter on Chronovore Clock. Then if there are ten or more time counters on it, remove all time counters from it and end the turn.

Flying
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Whenever Outrider Captain attacks, search your library for a creature card with mana value 1 or less, put it onto the battlefield tapped and attacking, then shuffle.

Deathtouch
{U/B}: Change a target of target spell or ability that targets Serafina to another creature you control.
Whenever Serafina deals damage to a player, at the beginning of the next end step, that player loses life equal to the life they lost this turn.

Flying, vigilance
If a nonland permanent entering the battlefield would cause a triggered ability of a permanent you control to trigger, you may have that ability trigger an additional time. If you do, each opponent copies that ability and may choose new targets for the copies.

Choose one —
• Target attacking creature gets +2/+2 until end of turn.
• Destroy target artifact.

When Mana Rose enters, you gain 2 life and scry 2.
{1}, {T}: Add one mana of any color.

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
When Vedalken Reshaper enters, return target instant or sorcery card from your graveyard to your hand.

Harvest (You may tap any number of creatures you control as you cast this spell. If you do, reduce this spell's mana cost by their total power.)
Create a 5/5 colorless Scarecrow artifact creature token with “This creature can't block or harvest.”
Flashback {8}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Put a +1/+1 counter on target creature. That creature gains first strike until end of turn.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Create a tapped colorless enchantment land token named Paradise with hexproof and “{T}: Add one mana of any color.”
Flashback—{1}{G}, Sacrifice a creature or land. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

{T}: Add {C}.
{T}, Exile two cards from your graveyard: Add {U} or {R}.

Destroy target artifact or enchantment with mana value 4 or less.

Counter target permanent spell. (Then exile this card. You may cast the creature later from exile.)

({T}: Add {W}.)
As Calcified Dunes enters, you may pay 1 life. If you don't, Calcified Dunes enters tapped.

Inscrutable Realms enters tapped unless you control two or more other lands.
{T}: Add {W}.
{T}, Pay 1 life: Add {G} or {U}.

Firehearth Halls enters tapped unless you control a basic Mountain.
{T}: Add {R}.
{R}{R}: Firehearth Halls becomes a 1/1 red Dwarf Warrior creature with double strike until end of turn. It's still a land.

Flying
Whenever another Spirit or another creature with flying you control enters, put a +1/+1 counter on Tattergeist.

When a creature you control scavenges Harvest Reaper, search your library for a colorless card, reveal it, put it into your hand, then shuffle.
Scavenge {4} ({4}, 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.)