msem-instigator

When Carrion Gourmet enters, each player sacrifices a creature.
Whenever another creature dies, put a +1/+1 counter on Carrion Gourmet.

Archive 6 (As this enters, shuffle the top six cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever a creature or planeswalker you control dies, you may play a card from the archived library. (You still pay its costs.)

Performer of Winds can't be blocked.
When Performer of Winds enters, remove a counter from up to one target permanent you control.

Dreamscape enters tapped with two charge counters on it.
{T}: Add {C}.
{T}, Remove a charge counter from Dreamscape: Add one mana of any color.

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. If that creature has flying, transform Mounting Up.

When Dwarven Tunnelers enters, create a tapped Treasure token.
{T}: Target creature with power 2 or less can't be blocked this turn.

{T}, Mill a card: Add {G}.
{X}{U}{B}, {T}, Exile a permanent card with mana value X from your graveyard: Create a tapped token that's a copy of it, except it's an X/X Elemental creature in addition to its other types.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 0/4 white Wall creature token with defender.
II — Put a +1/+1 counter on up to one target creature.
III — Until your next turn, each creature you control assigns combat damage equal to its toughness rather than its power.

When Globule of Agony enters or leaves the battlefield, target player loses 1 life.
{2/B}, {T}, Sacrifice Globule of Agony: Draw a card.

When Horn of Seasons enters, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equipped creature gets +3/+0.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Flying
Whenever Hecatomb Haunter enters or attacks, up to one other target nonland permanent phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

Blooming Needles enters tapped unless you control another Desert.
{T}: Add {R} or {G}.

Hexproof
Deploy 4 (As this enters, you may tap any number of other creatures you control with total power 4 or more.)
When Hamlet Witch enters deployed, return target card from your graveyard to your hand.

Whenever a land you control enters, put a +1/+1 counter on target creature you control.

Choose any number —
• Counter target spell unless its controller pays {X}.
• Draw X cards, then discard a card.
• Create a tapped X/X blue Elemental creature token with flying.
Foretell {X}{U}{U} (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.)

When Inspired Blade enters, if you control another Warrior, draw a card.

When AOSE Lab Tech enters, draw three cards, then discard two cards unless you discard an artifact card.

Flash
Enchant creature
Enchanted creature gets +1/+1 and has first strike.

When Crackling Palm Ascetic enters, target creature gains double strike until end of turn.

[+1]: Mill four cards, then return up to one creature card milled this way to your hand. You may activate a different loyalty ability Vivien has this turn.
[+1]: Create a 2/2 green Cat Spirit creature token with “When this creature dies, you gain 2 life.”
[–3]: Choose target creature you don't control. If it has flying, destroy it. Otherwise, up to one target creature you control deals damage equal to its power to that creature.
[–9]: Create four 4/4 green Hydra creature tokens. Creatures you control gain trample and haste until end of turn.

When Undead Banneret enters, if you control a legendary creature, each opponent loses 4 life.

{2}{R}: Thespian Soldier gains first strike until end of turn.

Creatures you control enter with a +1/+1 counter on them if you spend three or more colors of mana to cast them.

Equipped creature gets +1/+1.
Equipped creature has “When this creature dies, if it's not a token, create a token that's a copy of it except it's a colorless Spirit Dragon with flying in addition to its other abilities.”
Equip {2}

Exile target creature or planeswalker card from a graveyard. Search its controller's hand, graveyard, and library for any number of cards with the same name as that card and exile them. Then that player shuffles.