msem-instigator

Whenever an opponent casts a noncreature spell, create a Treasure token. (They're artifacts with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Codex — Hannah, Aethertechnician; Flynn Skara; Pidge, Tinkering Courier; Reyhsia, Truth Chaser. (As this enters, conjure its contents into a shuffled face-up additional library.)
You may spend mana as thought it were mana of any color to cast this codex's contents.
Sacrifice Karina's Connections: Copy target activated ability of one of its contents. You may choose new targets for the copy.

{2}{R}, Tap an untapped creature or Karina planeswalker you control: Copy target instant or sorcery spell, activated ability, or triggered ability. You may choose new targets for the copy. Activate this ability only once each turn.

Equipped creature gets +2/+2.
Whenever equipped creature attacks, the next time an instant or sorcery source you control would deal damage to a creature, player, or planeswalker this turn, it deals that much damage plus 2 instead.
Equip {2}

Target Vehicle creature you control deals damage equal to its power to any target. If a creature or planeswalker dealt damage this way would die this turn, exile it instead.

Flash
Enchant creature
Whenever enchanted creature becomes the target of an ability or spell you don't control or leaves the battlefield, enchanted creature deals 3 damage to any target.

Kernel Barrage deals damage to target creature or planeswalker equal to the number of spells you've cast this turn (including this one).
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Enchant opponent
Creatures attacking enchanted player get +2/+0.
{R}, Discard Kernel Flare: Draw a card.

Cast Khalizors' Last Stand only during your postcombat main phase.
Gain control of target creature until end of turn. Untap all creatures you control. They gain haste until end of turn. After this phase, there is an additional combat phase followed by an additional main phase.

Choose one —
• Kilnfire deals 1 damage to each creature and planeswalker target player controls.
• Destroy target artifact.

Add two mana in any combination of colors. (Then exile this card. You may cast the creature later from exile.)

When Kinken, the Dragon's Breath enters, draw a card, then choose a creature card name.
Whenever a creature you control with the chosen name attacks, you may pay {1}. If you do, create a token that's a copy of it and that's tapped and attacking, except it isn't legendary. Exile the token at the beginning of the end step.

Whenever you cast a spell that targets one or more permanents you don't control, gain control of those permanents until end of turn. Untap them. They gain haste until end of turn.

Koth's Retaliation deals 4 damage to target creature. When that creature dies this turn, exile its controller's graveyard.

[+1]: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.
[–2]: Koth, One True Hero deals damage to target creature equal to the number of Mountains you control.
[–7]: Create X 3/1 red Elemental creature tokens with trample and haste, where X is the number of Mountains you control.

Destroy target land. Create a 1/1 red Goblin creature token.

Target creature you control gets +3/+1 and gains trample until end of turn.
Showcase {3}{R}{R} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

At the beginning of combat on your turn, you may have Kym, New Hope become a 4/2 Warrior creature with first strike and haste until end of turn. (They don't lose loyalty while not a planeswalker.)
[+1]: Create a red enchantment token named Blitz with “Whenever you attack, target attacking creature gets +1/+0 until end of turn.”
[–2]: Whenever you attack with one or more creatures this turn, Kym, New Hope deals that much damage to any target.

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Lag Spike deals 3 damage to target [blocking] creature.

{T}: Add {R}.
Whenever you cast a spell from anywhere other than your hand, copy that spell. You may choose new targets for the copy.

Choose one —
• Destroy target artifact. Lamplight Explosion deals 1 damage to each opponent.
• Lamplight Explosion deals 1 damage to each creature your opponents control.

Gain control of target land.

Up to two target creatures can't block this turn.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Target creature gets +X/+0 until end of turn, where X is the number of instant and sorcery cards in your graveyard.

Lava Plume deals 3 damage to any target.
At the beginning of each end step, if you have 5 or less life, you may pay {R} and exile Lava Plume from your graveyard. If you do, it deals 3 damage to any target.