msem-instigator

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Shrouded Cackler can't block.

At the beginning of each player's end step, if they aren't horrific, Bloody Valentine deals 2 damage to that player. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

Exile target creature. If its power is 3 or greater, return that card to the battlefield under its owner's control at the beginning of the next end step.

Whenever a creature enters this turn, destroy it.

Triumvirate Infiltrator has flying as long as you control another Elemental.

Descended Meadow enters tapped.
{T}: Add {G} or {U}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

First strike (This creature deals combat damage before creatures without first strike.)
Whenever you cast an instant or sorcery spell, Flamemaster Insurgent gets +X/+0 until end of turn, where X is that spell's mana value.

Concord — Whenever Bubbledome Captain attacks, if there are four or more card types among permanents you control, each other attacking creature gets +1/+1 until end of turn.

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

{4}{B}{R}: Exile Watch the World Fade from your hand with seven apocalypse counters on it.
At the beginning of your upkeep, if Watch the World Fade is exiled, remove an apocalypse counter from it. If you do, each opponent loses 3 life unless they discard a card or sacrifice a nonland permanent. When you remove the last counter this way, each player loses the game.

Equipped creature has flying.
Equip {3}

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Whenever a marked creature an opponent controls dies, create a Food token. (It's an artifact with “{2}, {T}, Sacrifice this artifact: You gain 3 life.”)

When Tinyvale Trappings enters, you may attach it to target creature you control with mana value 2 or less.
Equipped creature gets +3/+1.
Equip {3}

Draw a card.
Showcase {3}{U} (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.)

Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.
{5}{B}, Sacrifice Manipulations of the Div: It deals 4 damage to target player or battle and you gain 4 life. Activate only as a sorcery.

{T}: Add {C}.
Satrapies you control have “{1}{G}, {T}: Put a +1/+1 counter on target creature. Activate only as a sorcery.”

Whenever you tap a land for mana, add an additional one mana of any color.
{8}{G}{G}: Creatures you control get +2/+2 and gain trample until end of turn.

Destroy target enchantment. If it's a Curse, you gain 3 life.

You may play Paradise Reef from your graveyard as long as seven or more cards are in your graveyard.
Paradise Reef enters tapped.
{T}: Add {G} or {W}.
Cycling {1}{G}{W} ({1}{G}{W}, Discard this card: Draw a card.)

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

{T}: Add {C}.
{T}, Pay 1 life: Add {U}.
{4}{U}, {T}, Sacrifice Verdant Oasis: Draw two cards. Activate only as a sorcery.

Enchant creature
Enchanted creature gets -X/-X, where X is 1 plus the number of counters on it.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
[+1]: Scry 1. If you're in a renaissance, draw a card.
[–2]: Return target nonland permanent to its owner's hand if its mana value is 3 or less or if you're in a renaissance.
[–6]: Create two 8/8 blue Kraken creature tokens. If you're in a renaissance, take an extra turn after this one.

First mate—Each nonland card in your starting deck has “destroy,” “die,” “graveyard,” and/or “mill” in its printed rules text. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Deathtouch
When Marisa enters, if it was cast, you may put target permanent card from a graveyard onto the battlefield under your control.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Create a 1/1 red Satyr creature token with “This creature can't block.”
[Lore III] Creatures you control get +1/+0 until end of turn.