msem-instigator

At the beginning of your end step, you may mill two cards. If you do, you gain 2 life.
[+1]: You may discard a card. If you do, draw a card.
[–2]: Exile up to six cards from your graveyard. Create a 1/1 red and green Spirit creature token for each two cards exiled this way.
[–6]: You may cast a card from your hand or graveyard without paying its mana cost. If it has {X} in its mana cost, X is 6.

[+1]: Create three 1/1 white Warrior creature tokens. They gain haste.
[0]: Until end of turn, each creature and planeswalker you control becomes a 3/3 Warrior creature and gains indestructible. (Permanents don't lose loyalty while they're not a planeswalker.)
[–2]: Choose tapped or untapped. Seto San deals 3 damage to each creature with the chosen attribute.

[+1]: Until your next turn, whenever up to one target permanent deals damage to another permanent or player, it deals that much damage to itself.
[–X]: When you next cast a noncreature spell with mana value X or less this turn, copy it. You may choose new targets for the copy.
[–2]: Create an X/X blue Spirit creature token, where X is the number of colors of mana you've spent to cast spells this turn.

Enchant player
If enchanted player would shuffle their library, instead that player chooses a permanent they control and a card from their hand, shuffles them into their owner's libraries, then loses 3 life.

Unstoppable Slaughter deals 1 damage to each creature and each player. Whenever a creature dealt damage by Unstoppable Slaughter this turn dies this turn, repeat that process.

Target creature gets +2/+2 until end of turn.
Wanderlust — If you control four or more differently named lands, that creature gets +4/+4 until end of turn instead.

[+2]: Create a 2/2 red Werewolf creature token with first strike and haste.
[–3]: Tanya deals 3 damage to each creature that's not a Wolf or a Werewolf.
[–8]: For each permanent your opponents control, that player sacrifices it unless they have Tanya deal 2 damage to them.

[+1]: Tanya, the Mooncursed becomes a legendary 3/1 red Werewolf creature with first strike until end of turn.
[–2]: Tanya, the Mooncursed deals 3 damage to target creature or planeswalker.
[–4]: Destroy target nonbasic colorless permanent.

Destroy target creature. End of the Road deals damage equal to that creature's power to that creature's controller or a planeswalker that player controls.

Archive 6 (As this enters, shuffle the top six cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever a creature or planeswalker you control dies, you may play a card from the archived library. (You still pay its costs.)

As an additional cost to cast this spell, you may sacrifice three artifacts.
Search your library for an artifact card, reveal it, put it into your hand, then shuffle. If you sacrificed three artifacts as you cast this spell, you may put a noncreature artifact card from your hand onto the battlefield.

Flash (You may cast this spell any time you could cast an instant.)
When Replicator Mage enters, you may create a token that's a copy of target creature that's attacking you. Exile that token at end of combat.

Wanderlust — When you cast this spell, you may copy it if you control four or more differently named lands.
Exile the top card of your library. Until the end of your next turn, you may play that card. Create a 1/1 Scout creature token that's all colors.

Untap all basic lands you control.
Draw a card.

Escalate {G} (Pay this cost for each mode chosen beyond the first.)
Choose one or both —
• Target creature you control gains deathtouch and indestructible until end of turn.
• Target creature you control fights target creature you don't control.

Counter target spell unless its controller pays {1} for each card in their graveyard.

Flying
Whenever you cast a spell from exile, each opponent loses 2 life.

This spell costs {X} less to cast, where X is 20 minus your life total.
First strike, menace, trample

First strike
When Mutilated Warrior enters, you may have it deal damage to each player equal to the number of Warriors you control.

Sear Flesh deals 3 damage to target creature or planeswalker. If you've cast another spell this turn, it deals 5 damage instead.

Flying, ward {2}
Intisuyu's Masterpiece gets +X/+X, where X is the number of artifacts and/or enchantments you control.

Flash
If a +1/+1 counter would be put on another creature, that counter is put on Grafted Physician instead.

When Unmasker of Fate's Design enters, look at target player's hand. Choose a nonland card from it and exile that card with a puzzle counter on it. As long as that card has a puzzle counter on it, that player may pay {2} and 1 life at any time. If they do, return the exiled card to their hand.

Once each turn, when you sacrifice a land, you may add one mana of any color. Until end of turn, you don't lose this mana as steps and phases end.

Exile up to one target creature.
Coalesce {5}{B}{B} (You may cast this from your graveyard for {5}{B}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Whenever Consign to Oblivion deals damage to a permanent, exile that permanent.