msem-instigator

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)

When Seeker of Far-Off Lands enters, search target opponent's library for a land card, put it onto the battlefield tapped under your control, then that player shuffles.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each opponent discards a card and loses 2 life.
II — Exile target card from a graveyard. If a creature card was exiled this way, you gain 2 life.
III — At the beginning of the next end step, you gain 3 life if an opponent lost life this turn and each opponent loses 3 life if you've gained life this turn.

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

When Aerie Bell-Warden enters, if it's in a pack, you gain 5 life. (Two or more creatures you control with equal power are in a pack.)

Valley Falls enters tapped unless you control two or more white and/or blue permanents.
{T}: Add {W} or {U}.

Warden of the Fronds' power and toughness are each equal to the number of Forests you control.
Warden of the Fronds has indestructible as long as you control five or more lands.

Flying
Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Lunar Flock has vigilance as long as you're in a renaissance.

Pressure {2}{G}{G} (You may cast this spell for its pressure cost if there are seven or more cards in your graveyard.)
Trample, hexproof
Shambling Dreadreef's power and toughness are each equal to the total number of land cards you own on the battlefield and in your graveyard.

[+1]: The next instant or sorcery spell you cast this turn costs {1} less to cast.
[–4]: Until end of turn, whenever you cast an instant or sorcery spell, Merkurio deals 2 damage to any target.
[–8]: Exile the top seven cards of your library. You may cast any number of instant and sorcery cards from among them without paying their mana costs.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Sacrifice a land: Desperate Ravager gets +2/+0 and gains haste until end of turn.

Schoolmaster gets +1/+1 for each other Merfolk you control.
When Schoolmaster enters, create a 1/1 white Merfolk creature token.

{1}, Sacrifice Penny Dreadful: Target creature can't attack or block this turn.
{1}, Sacrifice Penny Dreadful: Draw a card.

Whenever you draw a card, put a dream counter on Stargazing.
Remove seven dream counters from Stargazing and exile it: Shuffle your hand and graveyard into your library, then draw seven cards.

Creatures you control get +2/+1 until end of turn.

Return target creature or land card from your graveyard to your hand.

Whenever equipped creature attacks, it gains deathtouch until end of turn.
Sacrifice Bandit's Dagger: Target player dealt damage by equipped creature this turn reveals their hand. You choose a nonland card from it. That player discards that card.
Equip {2}

Equipped creature gets +2/+2.
Art of war — At the beginning of your end step, if equipped creature dealt damage to an opponent this turn, you may return target creature card from your graveyard to your hand.
Equip {2}

Fertile Steppe enters tapped unless you have 15 or less life.
{T}: Add {G} or {W}.

Whenever you attack, put a hatching counter on Greatwyrm's Egg. Then you may sacrifice it. If you do, create a tapped and attacking X/X red Dragon creature token with flying and haste, where X is the number of hatching counters on Greatwyrm's Egg.

Up to two target creatures each get -3/-0 until end of turn. Tap those creatures. They don't untap during their controller's next untap step.