Have

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Clue

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Lambholt Ravager

Whenever you cast a noncreature spell, this creature deals 2 damage to each opponent.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Lambholt Raconteur

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Lambholt Raconteur // Lambholt Ravager

Thirst for Discovery

Draw three cards. Then discard two cards unless you discard a basic land card.

Mountain

Increasing Vengeance

Copy target instant or sorcery spell you control. If this spell was cast from a graveyard, copy that spell twice instead. You may choose new targets for the copies.
Flashback {3}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Artful Dodge

Target creature can't be blocked this turn.
Flashback {U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Kessig Flamebreather

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Thermo-Alchemist

Defender
{T}: This creature deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap this creature.

Copy

(This token can be used to represent a token that's a copy of a permanent.)

Dual Casting

Enchant creature
Enchanted creature has "{R}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy."

Nephalia Academy

If a spell or ability an opponent controls causes you to discard a card, you may reveal that card and put it on top of your library instead of putting it anywhere else.
{T}: Add {C}.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Investigator's Journal

This artifact enters with a number of suspect counters on it equal to the greatest number of creatures a player controls.
{2}, {T}, Remove a suspect counter from this artifact: Draw a card.
{2}, Sacrifice this artifact: Draw a card.

Bonfire of the Damned

Bonfire of the Damned deals X damage to target player or planeswalker and each creature that player or that planeswalker's controller controls.
Miracle {X}{R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Ghastly Mimicry

Enchant creature
At the beginning of your upkeep, create a token that's a copy of enchanted creature, except it's a Spirit in addition to its other types.
If Ghastly Mimicry would be put into a graveyard from anywhere, exile it instead.

Mirrorhall Mimic

You may have this creature enter as a copy of any creature on the battlefield, except it's a Spirit in addition to its other types.
Disturb {3}{U}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Mirrorhall Mimic // Ghastly Mimicry

Snapcaster Mage

Flash
When this creature enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Sulfur Falls

This land enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Desperate Ravings

Draw two cards, then discard a card at random.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Shreds of Sanity

Return up to one target instant card and up to one target sorcery card from your graveyard to your hand, then discard a card. Exile Shreds of Sanity.

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Vadrik, Astral Archmage

If it's neither day nor night, it becomes day as Vadrik enters.
Instant and sorcery spells you cast cost {X} less to cast, where X is Vadrik's power.
Whenever day becomes night or night becomes day, put a +1/+1 counter on Vadrik.

Stormcarved Coast

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Island

Arcane Melee

Instant and sorcery spells cost {2} less to cast.

Cackling Counterpart

Create a token that's a copy of target creature you control.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Desolate Lighthouse

{T}: Add {C}.
{1}{U}{R}, {T}: Draw a card, then discard a card.

Secrets of the Key

Investigate. If this spell was cast from a graveyard, investigate twice instead. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Flashback {3}{U}

Curse of Echoes

Enchant player
Whenever enchanted player casts an instant or sorcery spell, each other player may copy that spell and may choose new targets for the copy they control.

Mirrorwing Dragon

Flying
Whenever a player casts an instant or sorcery spell that targets only this creature, that player copies that spell for each other creature they control that the spell could target. Each copy targets a different one of those creatures.