msem-instigator

When Warfan of Changing Winds enters, draw a card.
Whenever a card you own is exiled from anywhere, you may put it on the bottom of your library.

When Pensive Songwriter enters, you may copy and then exile an instant or sorcery card with mana value 2 or less from your hand. Cast the copy without paying its mana cost. You may cast the card as long as it remains exiled.

At the beginning of your upkeep, each opponent mills cards equal to the number of card types among permanents you control.

{1}, {T}, Sacrifice Looking Glass: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Kindle 1—{1} ({1}, Exile this card from your graveyard: Create a 1/1 colorless Elemental creature token. Kindle only as a sorcery.)

Counter target spell that targets you or a permanent you control. If that spell targeted a creature, put a +1/+1 counter on that creature.

Flying, lifelink
Whenever another creature you control attacks, until end of turn, that creature gets +2/+0 if it's red, +0/+2 if it's green, gains lifelink if it's white, and gains flying it if it's blue.

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

When Bearer of Tormented Truths enters, look at target player's hand. You may exile a nonland card from among them. If you do, that player draws a card.
You may play cards exiled with Bearer of Tormented Truths, and you may spend mana as though it was mana of any color to cast them.

Vigilance
When Worn Peacekeeper dies, create a 1/1 white Soldier creature token with vigilance.

Codex — Aspiring Dragon; Scrappy Hatchling; Skiviar Scraplord; Blizzard Dragon; Cloud Swine; Gold Retriever; Ilieth, Transcendent. (As this enters, conjure its contents into a shuffled face-up additional library.)
At the beginning of your upkeep, you may put a card from this codex's library on the bottom of that library.

Return target spell to its owner's hand.
Draw a card.

{2}, {T}: Prevent all combat damage that would be dealt to and dealt by target creature this turn.

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.

{G}, {T}: Put a +1/+1 counter on Bloodleaf Tracker for each creature that entered this turn.

When Leech-Ridden Corpse dies, each opponent loses 1 life and you gain 1 life.

When Runed Servitor dies, each player draws a card.

Trample
When Stensia Cavalcade enters, create two Weapon tokens. (They're Equipment artifacts with “Equipped creature gets +1/+1” and equip {2}.)

Concord — You may cast this spell as though it had flash if there are four or more card types among permanents you control.
When Krill-Clan Guardian enters, it fights up to one other target creature. If that creature would die this turn, return it to its owner's hand instead.

Target creature can't block until end of turn. If that creature had a Steed attached to it, unattach that Steed and it can't block until end of turn.
Draw a card.

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.)

Equipped creature gets +0/+2.
When equipped creature dies, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Equip {1}

{3}: Put a +1/+1 counter on Tinkerer's Assistant.

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, until end of turn, you may spend mana as though it were mana of any color to cast spells with the same name as that card and spells with that name can't be countered.

Sunken Cavern enters tapped unless another player controls a land that could produce {U} or {R}.
{T}: Add {U} or {R}.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] You gain 1 life.
[Lore III] Target creature you control gains first strike until end of turn.