msem-instigator

Cannoncoil Hermit enters with X +1/+1 counters on it.
{1}, {T}: Put a +1/+1 counter on Cannoncoil Hermit.
{1}, {T}, Remove a +1/+1 counter from Cannoncoil Hermit: It deals damage equal to its power to any target.
{3}: Untap Cannoncoil Hermit.

{T}: Add {C}.
{T}, Pay 1 life: Add {U} or {R}.

When Capac's Envoy enters, draw a card.
If one or more players would draw one or more cards except the first draw of a draw step, instead each player may draw up to the greatest number of cards that would have been drawn this way.

Exile any number of target artifacts and/or enchantments you control, then return them to the battlefield under your control.

Creatures you control have haste and attack each combat if able.
Attacking Soldiers you control get +1/+0.

Gain control of target creature.

Search your library for a card and put it into your hand, then shuffle. You lose life equal to the number of cards in your hand.

Careless Violence deals 2 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Until end of turn, all creatures gain deathtouch and “When this creature dies, its controller loses 2 life.”

Flash
When Caronas, Eon Wanderer enters, you gain 2 life and draw two cards if Caronas, Eon Wanderer isn't on the battlefield.
{2}{W}{U}, Discard two cards: Aetherize Caronas. (To aetherize, create a token that's a copy of it, then exile that token.)

When Carrion Scythe enters, if you cast it, you may return target creature card from your graveyard to the battlefield, then attach Carrion Scythe to it.
Equipped creature gets +1/+1 and has deathtouch.
Equip {2}

I, II — Scry 2.
Discovery — Whenever a land you control enters, if it doesn't have the same name as another land you control, draw a card.

Vanishing 3 (This permanent enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a time counter is removed from a permanent you control, Carve a Path deals 1 damage to any target.

Glitch {1} (Remove one [restriction] for each time you pay the glitch cost.)
Each opponent loses 3 life, discards a card, sacrifices a creature, then sacrifices a land.
[You lose 3 life.] [Discard a card.] [Sacrifice a creature.] [Sacrifice a land.]

Flash
When Cast Out enters, exile target nonland permanent an opponent controls until Cast Out leaves the battlefield.
Cycling {W} ({W}, Discard this card: Draw a card.)

Reveal cards from the top of your library until you reveal a card with a lesser mana value than the previous card, then put all cards revealed this way into your hand.

Whenever another creature or enchantment you control enters, you gain 1 life.
{3}{W}{W}, Pay 5 life: Castigated Sister becomes a 5/5 Angel Horror with flying. (This effect doesn't end at end of turn.)

Casualty of War deals 4 damage to target creature or planeswalker.
{2}{R}{R}, Exile Casualty of War from your graveyard: Arm up to two target creatures you control. Activate only as a sorcery. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Flying, haste
When Cataclysmic Skytyrant enters, sacrifice all other non-Dragon creatures you control. For each creature sacrificed this way, create a 3/3 red Dragon creature token with flying.

Choose one. If you're horrific, you may choose both instead. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)
• Destroy target artifact.
• Catastrophic Crash deals 3 damage to target creature.

As an additional cost to cast this spell, discard two cards.
Draw three cards.

[+1]: Create a 1/1 red Human creature token with haste.
[–2]: Untap all creatures you control. Until end of turn, they gain “{T}: This creature deals 1 damage to each opponent.”
[–6]: You get an emblem with “Whenever a creature becomes tapped, this emblem deals 2 damage to any target and you gain 2 life.”

Renown 2 (When this creature deals combat damage to a player, if it isn't renowned, put two +1/+1 counters on it and it becomes renowned.)
Whenever Cauldish Arrogant becomes blocked by one or more creatures, reveal the top card of your library. Cauldish Arrogant deals damage equal to that card's mana value to each creature blocking it. Then put that card into your hand.

Bleed {1}{B}{B} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
All creatures get -4/-4 until end of turn.

Haste
Caulte Axeslinger gets +2/+2 as long as any opponent lost exactly 3 life this turn.