msem-instigator

Cresting Bay enters tapped unless you control a basic Island.
{T}: Add {U}.
{2}{U}{U}: Until end of turn, Cresting Bay becomes a 3/3 blue Elemental creature with “Whenever this creature attacks, you may draw a card then discard a card.” It's still a land.

Haste
{R}{R}{R}, Discard your hand, Sacrifice Crimson Knight: Draw three cards.

Crimson Sunrise deals 4 damage to each creature. Each player sacrifices four nonbasic lands.

{T}, Tap two other untapped creatures you control: Add two mana of any one color.

({T}: Add {B} or {R}.)
Whenever Crumbling Precipice becomes tapped, you lose 1 life unless you control two or more basic lands.

Menace, haste, decayed (This can't block. When it attacks, sacrifice it at end of combat.)
At the beginning of combat on each of your turns, if you have three or more creature cards in your graveyard and haven't controlled a creature named Crypt Gnawer this turn, return Crypt Gnawer from your graveyard to the battlefield.

Search your library for a card, exile it face down, then shuffle. For as long as that card remains exiled, you may cast it. It costs {2} more to cast this way if you don't control a legendary creature as you cast that spell.

Flying
Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
Whenever a cursed opponent draws a card, you may draw two cards.

({T}: Add {U} or {R}.)
Whenever Crystal Cavern becomes tapped, you lose 1 life unless you control two or more basic lands.

Flying
Whenever you make first contact, Curio Hellkite deals 2 damage to any target. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Enchant opponent
Whenever enchanted player plays a land, you may put a land card from your hand onto the battlefield.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Damning Flames deals 3 damage to any target. If this spell's tithe was paid, it deals 6 damage instead.

Exile target creature, return it to the battlefield tapped under its owner's control, then choose one —
• Put a +1/+1 counter on it.
• Put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

You don't lose the game for having 0 or less life.
Whenever you're dealt damage, mill that many cards.
{B}, Pay 2 life: Put target card in your graveyard on the bottom of your library.

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card.
Create a Function token with “Draw a card if a player discarded a card this turn.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Whenever you cast a spell, if it shared a color with the last spell you cast this turn, put two +1/+1 counters on Defected Android.

Repeat the following process X times. Reveal the top two cards of your library. Put one of them into your hand and the other into your graveyard.

This spell costs {2} less to cast for each creature that died this turn.
Flying, trample

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Haste
Whenever you cast a creature spell, it gains bloodthirst 1. (Multiple instances of bloodthirst on a spell stack.)

Whenever a creature you control dies, put a loyalty counter on Dias, Freed from Belief.
[0]: Create a 2/1 black Nightmare creature token with “This creature can't block.”
[–X]: Destroy target creature or planeswalker unless an opponent pays twice X life.

Draw two cards. Then if this spell wasn't cast from your hand, create a Function token with “Compose.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

When Diligent Fishermen enters, look at the top four cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Counter target spell.
If you countered a spell with mana value 2 or less this way, manifest dread. (Look at the top two cards of your library, then put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Casualty 1 (As you cast this spell, you may sacrifice a creature with power 1 or greater. When you do, copy this spell.)
All creatures get -2/-2 until end of turn

Whenever one or more creatures you control deal combat damage to an opponent, choose up to that many —
• Create a Weapon token and attach it to one of those creatures. (It's an Equipment with equip {2} and “Equipped creature gets +1/+1.”)
• Add {R}{W} at the beginning of your next main phase.
• Each player draws a card.