Goblin

Dungeon of the Mad Mage

Yawning Portal — You gain 1 life. (Leads to: Dungeon Level)
Dungeon Level — Scry 1. (Leads to: Goblin Bazaar, Twisted Caverns)
Goblin Bazaar — Create a Treasure token. (Leads to: Lost Level)
Twisted Caverns — Target creature can't attack until your next turn. (Leads to: Lost Level)
Lost Level — Scry 2. (Leads to: Runestone Caverns, Muiral's Graveyard)
Runestone Caverns — Exile the top two cards of your library. You may play them. (Leads to: Deep Mines)
Muiral's Graveyard — Create two 1/1 black Skeleton creature tokens. (Leads to: Deep Mines)
Deep Mines — Scry 3. (Leads to: Mad Wizard's Lair)
Mad Wizard's Lair — Draw three cards and reveal them. You may cast one of them without paying its mana cost.

Skeleton

Menace (This creature can't be blocked except by two or more creatures.)

The Monarch

At the beginning of your end step, draw a card.
Whenever a creature deals combat damage to you, its controller becomes the monarch.

Tomb of Annihilation

Trapped Entry — Each player loses 1 life. (Leads to: Veils of Fear, Oubliette)
Veils of Fear — Each player loses 2 life unless they discard a card. (Leads to: Sandfall Cell)
Sandfall Cell — Each player loses 2 life unless they sacrifice a creature, artifact, or land of their choice. (Leads to: Cradle of the Death God)
Oubliette — Discard a card and sacrifice a creature, an artifact, and a land. (Leads to: Cradle of the Death God)
Cradle of the Death God — Create The Atropal, a legendary 4/4 black God Horror creature token with deathtouch.

Baldur's Gate Wilderness

Crash Landing — Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Goblin Camp — Create a Treasure token.
Emerald Grove — Create a 2/2 white Knight creature token.
Auntie's Teahouse — Scry 3.
Defiled Temple — You may sacrifice a permanent. If you do, draw a card.
Mountain Pass — You may put a land card from your hand onto the battlefield.
Ebonlake Grotto — Create two 1/1 blue Faerie Dragon creature tokens with flying.
Grymforge — For each opponent, goad up to one target creature that player controls.
Githyanki Crèche — Distribute three +1/+1 counters among up to three target creatures you control.
Last Light Inn — Draw two cards.
Reithwin Tollhouse — Roll 2d4 and create that many Treasure tokens.
Moonrise Towers — Instant and sorcery spells you cast this turn cost 3 less to cast.
Gauntlet of Shar — Each opponent loses 5 life.
Balthazar's Lab — Return up to two target creature cards from your graveyard to your hand.
Circus of the Last Days — Create a token that's a copy of one of your commanders, except it's not legendary.
Undercity Ruins — Create three 4/1 black Skeleton creature tokens with menace.
Steel Watch Foundry — You get an emblem with "Creatures you control get +2/+2 and have trample."
Ansur's Sanctum — Reveal the top four cards of your library and put them into your hand. Each opponent loses life equal to those cards' total mana value.
Temple of Bhaal — Creatures your opponents control get -5/-5 until end of turn.

The Atropal

Lost Mine of Phandelver

Cave Entrance — Scry 1. (Leads to: Goblin Lair, Mine Tunnels)
Goblin Lair — Create a 1/1 red Goblin creature token. (Leads to: Storeroom, Dark Pool)
Mine Tunnels — Create a Treasure token. (Leads to: Dark Pool, Fungi Cavern)
Storeroom — Put a +1/+1 counter on target creature. (Leads to: Temple of Dumathoin)
Dark Pool — Each opponent loses 1 life and you gain 1 life. (Leads to: Temple of Dumathoin)
Fungi Cavern — Target creature gets -4/-0 until your next turn. (Leads to: Temple of Dumathoin)
Temple of Dumathoin — Draw a card.

The Initiative

Whenever one or more creatures a player controls deal combat damage to you, that player takes the initiative.
Whenever you take the initiative and at the beginning of your upkeep, venture into Undercity. (If you're in a dungeon, advance to the next room. If you're not, enter Undercity. You can take the initiative even if you already have it.)

Undercity

You can't enter this dungeon unless you "venture into Undercity."
Secret Entrance — Search your library for a basic land card, reveal it, put it into your hand, then shuffle. (Leads to: Forge, Lost Well)
Forge — Put two +1/+1 counters on target creature. (Leads to: Trap!, Arena)
Lost Well — Scry 2. (Leads to: Arena, Stash)
Trap! — Target player loses 5 life. (Leads to: Archives)
Arena — Goad target creature. (Leads to: Archives, Catacombs)
Stash — Create a Treasure token. (Leads to: Catacombs)
Archives — Draw a card. (Leads to: Throne of the Dead Three)
Catacombs — Create a 4/1 black Skeleton creature token with menace. (Leads to: Throne of the Dead Three)
Throne of the Dead Three — Reveal the top ten cards of your library. Put a creature card from among them onto the battlefield with three +1/+1 counters on it. It gains hexproof until your next turn. Then shuffle.

Undercity // The Initiative

Night

As it becomes night, transform all daybound permanents.
Permanents enter the battlefield nightbound.
If a player casts at least two spells during their own turn, it becomes day next turn.

(If it becomes day or night or if a daybound permanent enters the battlefield, track day/night for the rest of the game.)
As it becomes day, transform all nightbound permanents.
If a player casts no spells during their own turn, it becomes night next turn.