Magic does Dungeons and Dragons. Four decks about dungeon delving, Dragons, Equipment and exiling the top of your library.
Venturing enters one of three dungeon cards and moves you one room deeper each time, taking that room effect. It is a slow persistent engine that nobody can interact with, which is unusual for Magic.
The three dungeons are separate cards outside the game: a short aggressive one, a longer value one, and the Lost Mine. Choosing which to enter is part of the decision.
Enrage triggers when a creature is dealt damage. The Gruul deck sets it off on purpose rather than waiting for opponents to do it.
The Bant deck plays gear straight off the top of your library, which turns the usual voltron problem of drawing gear with no body into an advantage.
Adventures in the Forgotten Realms is the first Dungeons and Dragons crossover, and venturing into the dungeon is its signature. You track your progress on a separate card, take a small effect each step, and reach a payoff at the bottom.
The Commander decks split between that and more familiar archetypes: a Dragon deck, a voltron deck and a Rakdos exile engine that turned out to be the most popular commander in the box.
Venturing is slower than it looks. Each trigger moves you one room, so a deck that ventures twice a turn reaches the bottom of the Lost Mine in a few turns and a deck that ventures once a game gets a scry out of it. The Esper deck is the only one built to venture repeatedly, which is why it feels like a different product from the other three.
Prosper is the card that outlived the set. Exiling the top card of your library each turn and making a Treasure whenever you cast from exile is an engine that plugs into half a dozen archetypes, and the deck has been a common budget recommendation ever since.
Planar Portal is the deck to buy. Prosper alone turned into an archetype, and the shell around him already works.
Galea, Kindler of Hope · Storvald, Frost Giant Jarl
A Bant Voltron deck led by Galea, Kindler of Hope, play Auras and Equipment from the top of your library for free, suit up one massive creature, and swing for commander damage lethal while keeping your hand full.
Vrondiss, Rage of Ancients
A Gruul dragon deck from Adventures in the Forgotten Realms, led by Vrondiss, Rage of Ancients, trigger his enrage ability to flood the board with 5/4 Dragon Spirit tokens that deal damage on their way out.
Sefris of the Hidden Ways
An Esper dungeon-diving and reanimation deck from Adventures in the Forgotten Realms, led by Sefris of the Hidden Ways, venture into dungeons as creatures die and return, then reanimate any creature when you complete a dungeon.
Prosper, Tome-Bound
A Rakdos exile-and-treasure engine from Adventures in the Forgotten Realms, led by Prosper, Tome-Bound, exile the top of your library each turn to cast spells for free, generating Treasure tokens that fuel explosive follow-up turns.