msem-instigator

Return target instant or sorcery card with mana value 3 or less and without reconstruct from your graveyard to your hand.
Reconstruct {6}{U} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

As Alratha, Pearl of the Sand Sea enters the battlefield, you may have an opponent investigate. If you don't, it enters the battlefield tapped.
{T}: Add {U}.
{1}{U}, {T}: Investigate.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Exile each player's graveyard. Create a token that's a copy of a creature card exiled this way.
III — Create a token that's a copy of an artifact or enchantment card exiled with Around the Plane in Three Days.
Create a token that's a copy of a land or planeswalker card exiled with Around the Plane in Three Days.

Menace
When Azuma Hashiro, the Thronebreaker enters the battlefield, you may cast up to two cards from your opponents' graveyards without paying their mana costs. If those spells would be put into a graveyard, exile that card instead.

When Chiheisen, Terrace of Serenity enters the battlefield, draw a card, then choose a creature card name.
Spells you cast with the chosen name cost {2} less to cast.

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
When Dai Gui enters the battlefield, create a 1/1 green and blue Bird creature token with flying and “{T}: Add one mana of any color.”
{X}{X}{G}{U}: Demigod — You gain X life and you draw X cards. X can't be 0.
{X}{X}{G}{U}: God — Put up to X creature cards from your hand onto the battlefield.

{T}, Sacrifice an Equipment: Return target Equipment card from your graveyard to the battlefield. Activate only as a sorcery.

{2}{U}{B}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield with a finality counter on it. It gains myriad. (Whenever it attacks, for each opponent other than defending player, you may put a token that's a copy of this creature onto the battlefield tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

[+1]: Create a 1/1 white Warrior creature token.
[–1]: Another target permanent you control gains indestructible until your next turn.
[–8]: You get an emblem with “Creatures you control get +2/+2.” and “Prevent all damage that would be dealt to attacking creatures you control.”

Indestructible
As long as your devotion to white and blue is less than seven, Ephara isn't a creature.
You may cast creature and enchantment spells as though they had flash.
Whenever another creature or enchantment enters the battlefield under your control, you gain 1 life.

When Esiara, Skycaster's Infiltrator enters the battlefield, exile target spell with mana value 4 or less.
{1}{U}{U}, Discard two cards: Exile Esiara, then return it to the battlefield under your control.
{2}{U}{U}, {T}, Exile Esiara: Until end of turn, you may play cards you don't own from exile.

[+1]: Add {R} or {G}.
[–1]: Fatresya deals 2 damage to target creature. That creature can't block this turn.
[–5]: You get an emblem with “Creatures you control get +2/+2 and have haste and trample.”

{T}: Add {C}.
{3}, {T}, Sacrifice Hall of Random Access Memories: Return target artifact, instant, or sorcery card from your graveyard to your hand.

Trample
Other Dwarves and Elves you control get +1/+1.
If Harl and Finn or another Dwarf or Elf you control entering the battlefield or attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

As Harlowe, Thespian Extraordinaire enters the battlefield, choose a color and creature type.
Harlowe, Thespian Extraordinaire is the chosen color.
Harlowe, Thespian Extraordinaire is the chosen type in addition to its other types.

Flying
You may cast black spells with mana value 3 or less by paying life equal to their mana values rather than paying their mana costs.
{B}, Sacrifice another creature: You gain 3 life.

Advance {2} (Cast this for {2} to advance it as it enters. {2}: Advance this as a sorcery.)
Equipped creature gets +1/+1 for each artifact you control.
Equipped creature must be blocked by an additional creature for each time it and this artifact have advanced this turn to be blocked.
Equip {3}

Flying, lifelink
Other Demons you control have flying and lifelink.
If you would create a creature token, you may instead pay 5 life and create a 5/5 black Demon creature token.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Lord Jared, the Griffin Knight attacks, put a +1/+1 counter on each other attacking creature you control.

[+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.

Ferocious — Whenever a creature with power 4 or greater enters the battlefield under your control, Mieng, Who Dances With Dragons becomes a 4/4 Dragon creature with flying until end of turn.

Deception {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Ms. Moxie deals combat damage to a player, you may exile target nonland card with mana value 2 or less from your graveyard. If you do, cast a copy of that card without paying its mana cost.

You may cast instant and sorcery cards from your graveyard. Spend no more than one mana of each color to cast spells this way each turn. If a spell cast this way would be put into your graveyard, exile it instead.

{T}, Pay 1 life: Add {W}.
{6}{W}{W}{W}, Exile Rius, Temple of the Grandfather from your hand: Target player gains 20 life.

Saljan, Lord of the Disfigured and other Mutants you control get +1/+1 and have indestructible.
Whenever Saljan attacks or blocks, create a 1/2 black Mutant creature token.