msem-instigator

When Destiny Beyond Measure enters, tap each creature you control.
Creatures you control get +8/+8 and have “This creature enters tapped.”

({T}: Add {B} or {G}.)
Whenever Nomad's Township becomes tapped, you lose 1 life unless you control two or more basic lands.

You mill two cards, draw two cards, lose 2 life, and create two Treasure tokens. (They're artifacts with “{T}: Sacrifice this permanent: Add one mana of any color.”)

For each pair of basic land types, create a tapped colorless land token of those types. (The basic land types are Plains, Island, Swamp, Mountain, and Forest.)

Flash
Whenever another permanent dies, put a +1/+1 counter on Heyu.
{1}{G}: Heyu becomes a colorless Island land until end of turn.

Until end of turn, gain control of target creature and it gains haste and shimmer. Untap it. (Whenever it attacks this turn, create a tapped and attacking token that's a copy of it. Exile that token at the beginning of the end step.)

As Choked Estuary enters, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters tapped.
{T}: Add {U} or {B}.

All lands gain “{T}: Add one mana of any color” and lose all other abilities.

Frondpond Grotto enters tapped unless you played it from exile.
{T}: Add {U} or {B}.

When Project Head enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
{2}{U}, Exile Project Head: Shuffle your hand and graveyard into your library, then draw seven cards. Activate only if you control seven or more artifacts.

As an additional cost to cast this spell, sacrifice a creature.
Surveil 2, then draw a card. Create a Treasure token and a 1/1 black Bat creature token with flying and “This creature can't block.”

When Glowskate Channeler enters, create a green Aura enchantment token named Manta's Wings attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+2.”

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Put a +1/+1 counter on target creature you control.
III — Double the number of counters on target creature you control.
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Whenever a noncreature permanent enters, Petaldiver deals 1 damage to that permanent's controller.

This spell costs {1} less to cast if you control a Warrior.

When Hardlight Visionary enters, create a Function token with “Until end of turn, target creature becomes a 5/5 Dragon and gains flying.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Choose one —
• Unwrite deals 3 damage to target attacking or blocking creature.
• Destroy target artifact.
• Destroy target enchantment.

If a creature dealt damage by equipped creature this turn would die, exile that card and draw a card instead.
Equip {1}

Whenever you cast a noncreature spell, look at the top X cards of your library, where X is that spell's mana value. Put those cards on top of your library in any order.

Enchant player
At the beginning of enchanted player's end step, gain control of a permanent they control.

{T}: Add {B} or {G}.
{T}, Sacrifice Sigil of Growth: Add {B}{G}.

When Hamlet Swordmaster enters, create a Weapon token. (It's an Equipment artifact with “Equipped creature gets +1/+1” and equip {2}.)
Whenever Hamlet Swordmaster attacks while you control three or more artifacts, exile the top card of your library. You may play it this turn.
Artifact spells you cast cost {1} less to cast.

Enchant creature
Spirited (When this enters, you may activate one of its activated abilities without paying its cost.)
{1}: Enchanted creature can't attack or block this turn.

Flash
Flying, vigilance
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)