There are three main ways to upgrade Keep the Heroes Out: give the dungeon walls height, replace frequently handled tokens, or change the treasure chests. Start with one category if that is all your table needs.
Walls: change the scenery
The Magnetic Walls Set contains 48 sections: 25 with doors and 23 without. Built-in magnets connect the sections while you arrange the dungeon. It contains no resource tokens or treasure chests.
Keep doors, room connections, tiles and cards readable as you place the walls. These are scenery pieces; they do not change the map or the movement rules in your scenario.

Tokens: change the pieces you handle
The 56-piece Deluxe Token Set supplies five frogs, five traps, five coins, five books, five bones, 20 hearts, ten wands and one active-player torch. Choose it if you want replacement tokens while keeping the dungeon's current appearance.

Treasures: keep the hidden value usable
The Deluxe Treasure Set contains 12 chests and 30 numbered inserts with values 1–4. The chests have a slot for the original cardboard treasure token. Keep the required information hidden or revealed according to the scenario, rather than treating the decorative chest as a new rule.
When does the Dungeon Bundle make sense?
The Deluxe Dungeon Bundle combines the token, treasure and wall categories. It suits a table that wants all three. Buying the matching standalone sets as well would duplicate those categories. Check the bundle's itemised listing for its current contents instead of adding together every extra shown in separate product photographs.
For expansion-specific pieces or a particular scenario, compare its requirements before assuming a bundle covers everything. The game's BGG forums are a place to explore scenario questions; they do not certify accessory compatibility. This guide covers unofficial DeluxyGames physical accessories. The game, cards and expansions are not supplied.