msem-instigator

Dustchoked Outpost enters tapped.
When Dustchoked Outpost enters, create a 1/1 Scout creature token that's all colors. It gains haste until end of turn. Sacrifice it at the beginning of the next end step.
{T}: Add {R}.

Sacrifice two lands, Mill five cards: Return Jack, Horrific Harvester from your graveyard to your hand.
[+1]: You gain 2 life and each opponent loses 2 life.
[–2]: Return up to one target creature card and up to one target land card from your graveyard to your hand.
[–2]: Each opponent sacrifices the nonland permanent they control with the greatest mana value among permanents they control.

Vigilance, trample
Whenever another Horror you control enters, choose one —
• Destroy target artifact or enchantment.
• You gain 4 life.
• Apex Abomination fights another target creature.

Equipped creature has menace.
Sacrifice an artifact or enchantment: Equipped creature gets +2/+2 until end of turn.
Equip {1}

As an additional cost to cast this spell, sacrifice an artifact.
Draw three cards.

At the beginning of your upkeep, create a 1/1 green Saproling creature token.
Whenever a creature you control dies, put a +1/+1 counter on Heart of Spores.
{X}{G}: Move X +1/+1 counters from Heart of Spores onto target creature. Activate only as a sorcery.

I, II — Draw a card.
Discovery — Noncreature spells you cast cost {1} less to cast.

Flying, vigilance
Exile a creature card from your graveyard: Maligned Scavenger gets +1/+1 until end of turn.

At the beginning of your upkeep, mill two cards.

Defender
Territorial Fangwurm may attack as though it didn't have defender as long as you've cast a cryptic spell this turn. (Artifacts, enchantments, and modal spells are cryptic.)

When Pious Warden enters, choose one —
• Exile target creature you don't control until Pious Warden leaves the battlefield.
• Destroy target enchantment.
• You gain 5 life.

Treacherous Oasis enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}: Until end of turn, Treacherous Oasis becomes a Crocodile creature in addition to its other types. It can't be blocked this turn.
Scavenge {1}{U}{B}

Whenever you cast an enchantment spell, you draw a card and you lose 1 life.
Whenever one or more counters are put on an enchantment you control, you gain 1 life and each opponent loses 1 life.

Target creature gets +2/+0 until end of turn and can't be blocked except by three or more creatures this turn.
Flashback {U/R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Target creature you control gets +2/+0 and gains indestructible until end of turn. You lose 2 life.

({T}: Add {U}.)
Interlocked Waterways enters tapped.
{U}, {T}, Reveal a blue card from your hand: Untap target creature.

Enchant opponent
At the beginning of enchanted player's upkeep, they mill two cards.
{U}, Sacrifice Strange Tides: Shuffle up to four target cards from your graveyard into your library.

Return target creature card from your graveyard to your hand. (Then exile this card. You may cast the creature later from exile.)

Flying
When Morningheart Griffin dies, return target enchantment card from your graveyard to your hand.

Flash
When Crossroads Harrier enters, it deals 2 damage to target opponent or permanent an opponent controls unless that player has you draw a card.

Target instant or sorcery spell gains “This spell deals 4 damage to you.”

[+2]: Create two 0/0 colorless Reflection creature tokens.
[–2]: Distribute four +1/+1 counters among any number of target creatures you control. You may tap or untap each of those creatures.
[–7]: You get an emblem with “Creature tokens you control can't leave the battlefield.”

Vigilance
When Illari, Martyrized Tyrant enters, tap all other nonbasic permanents.
Players can't untap more than one nonbasic permanent during each of their untap steps.
When Illari dies, untap all permanents you control and you gain 5 life.

Other Pirates and Rogues you control get +1/+0.
Whenever you attack with three or more Pirates and/or Rogues, tap target creature.