msem-instigator

When Pensive Songwriter enters, you may copy and then exile an instant or sorcery card with mana value 2 or less from your hand. Cast the copy without paying its mana cost. You may cast the card as long as it remains exiled.

Choose target spell. If it's an instant, a sorcery, or you cast this spell from exile, copy it. You may choose new targets for the copy.
Prophecy {2}{U}{U} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

Menace, lifelink
Once during each of your turns, if you would gain life, you may create a tapped Treasure token instead.

As a spell you control is countered by a spell or ability an opponent controls while you control a Mountain, you may reveal Confront the Riddlemaster from your hand. When you do, cast it without paying its mana cost.
This spell can't be countered.
Confront the Riddlemaster deals 4 damage to any target.

Flying, haste
Whenever a nonbasic land becomes tapped, it deals 2 damage to its controller.
Whenever Kaor Awoken attacks, it gets +1/+0 until end of turn for each other Dragon you control.

Counter target spell if it shares a color with mana spent to cast Antimagic.

When Soulblade enters, exile target creature card with mana value 3 or less from your graveyard.
Whenever equipped creature attacks, create a token that's a copy of a card exiled with Soulblade that's tapped and attacking. Exile the token at end of combat.
Equip {1}

All creatures get -4/-4 until end of turn. If a creature would die this turn, exile it instead.

You may change any targets of target spell that targets you or a permanent you control. If you don't, counter that spell.

{T}: Add {C}.
{T}, Pay 1 life: Add {B}.
{5}{B}, {T}, Sacrifice Collapsing Ridges: Return target creature card from a graveyard to the battlefield under your control. Activate only as a sorcery.

Haste
Whenever Malformed Mongrel deals combat damage to a player, discard a card.

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.

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.

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.

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

{T}: Add {C}.
Discard Shikai's Redoubt: Exile up to two target cards from graveyards.

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

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

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

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

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

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.

Untap all basic lands you control.
Draw a card.

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.