msem-instigator

Whenever this creature enters or attacks, create a 2/1 white Soldier creature token. Exile up to one target nonland permanent with mana value 3 or less an opponent controls until that token leaves the battlefield.
Other permanents you control have ward {1}.

Overgrown Ruins enters tapped.
As Overgrown Ruins enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Choose creature or land, or choose both if you control a creature with power 4 or greater. Reveal the top five cards of your library. Put all cards revealed this way with a chosen type into your hand and the rest into your graveyard.

Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1.

When Ancestor's Skull enters, target creature gets +1/+0 and gains menace until end of turn.
{2}, Sacrifice Ancestor's Skull: Target creature gets +2/+0 and gains menace until end of turn.

Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Atuum Serpent enters, if tribute was paid, it gains defender. (This effect lasts indefinitely.)

Flash
When Purehorn Rescuer enters, return target permanent card with mana value X or less from your graveyard to the battlefield, where X is your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)

Create a 1/1 white Bird creature token with flying.
Monument {2}{W} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Create a 1/1 blue Pirate creature token or a 2/2 white Dwarf creature token.
III — Until end of turn, creatures you control gain “Whenever this creature attacks, draw a card, then discard a card unless this creature is a Pirate.”
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When Goremound enters, target creature you don't control gets -3/-3 until end of turn. All other creatures you don't control with the same name as that creature get -1/-1 until end of turn.
Evoke {1}{B} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Enchant creature
Enchanted creature has flying and “Sacrifice a creature: This creature gets +2/+1 until end of turn.”
When Fallen Ideal is put into a graveyard from the battlefield, return Fallen Ideal to its owner's hand.

Destroy target artifact.
Catalyze. (The next spell you cast this turn costs {1} less to cast.)

Equipped creature gets +2/+2.
Whenever equipped creature attacks, exile target nonland permanent defending player controls. For as long as that card remains exiled, its owner may cast it. (They still pay its costs.)
Equip {2}

Lifelink
Once each turn, when you draw a card, you may reveal it and a card you own from outside the game with a different name and the same mana cost. If you do, exile the first card and put the second into your hand. (Mana costs must be identical.)

Enchant opponent
Enchanted player plays with the top card of their library revealed.
You may cast the top card of enchanted player's library, and you may spend mana as though it were mana of any type to cast it.

Rapport — Whenever Tinkering Swarm and at least one other creature you control become tapped, create a token that's a copy of Tinkering Swarm.

Flash
When Mighty Beetle enters, you may put two +1/+1 counters on target creature you control.

When Leads Don't Die enters, mill four cards and you gain 4 life.
At the beginning of your upkeep, you may exile X cards from your graveyard and sacrifice Leads Don't Die. When you do, return target creature card with mana value X or less from your graveyard to the battlefield.

Equipped creature has first strike.
Whenever another creature you control dies, put a +1/+1 counter on equipped creature.
Equip {2}

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
As Ulek Wayfinder envisions a land card, you may put that card onto the battlefield tapped.

Equipped creature gets +2/+2 and has trample.
Equip {2}

Each player sacrifices a creature. (Then exile this card. You may cast the artifact later from exile.)

Choose X —
• Return target spell to its owner's hand.
• Scry 3.
• Draw a card.

Reach
Eerie Cocoons gets +1/+1 as long as you control another Insect.

{U}, Exile a card from your hand or graveyard that doesn't share a type with a card exiled by Tea of Augury: Draw a card.