Games like Once upon a Dungeon
Games like Once upon a Dungeon include Darkest Dungeon®, Tales of Maj'Eyal, The Binding of Isaac: Rebirth, Dungeons of Dredmor, and Shattered Pixel Dungeon. We matched them by the tags players give Once upon a Dungeon on Steam (RPG, Indie, Roguelike, Traditional Roguelike, and Dungeon Crawler): closest matches first, and among equally close ones the better-known games.

Darkest Dungeon®
Shared: RPG · Roguelike · Dungeon Crawler

Tales of Maj'Eyal
Shared: Roguelike · Traditional Roguelike · RPG

The Binding of Isaac: Rebirth
Shared: Indie · Roguelike · Dungeon Crawler

Dungeons of Dredmor
Shared: Roguelike · RPG · Traditional Roguelike

Shattered Pixel Dungeon
Shared: Traditional Roguelike · Roguelike · RPG

Stoneshard
Shared: RPG · Roguelike · Turn-Based

Noita
Shared: Roguelike · Indie · Dungeon Crawler

Hades
Shared: Indie · Roguelike · RPG

Slay the Spire
Shared: Roguelike · Turn-Based · Indie

Elin
Shared: RPG · Roguelike · Traditional Roguelike

Grim Dawn
Shared: RPG · Dungeon Crawler · Loot

Crown Trick
Shared: RPG · Roguelike · Dungeon Crawler

Dungeonmans
Shared: Roguelike · RPG · Traditional Roguelike

Wolcen: Lords of Mayhem
Shared: RPG · Indie · Singleplayer

The Binding of Isaac
Shared: Indie · Roguelike · Difficult

Hades II
Shared: Roguelike · RPG · Dungeon Crawler

ADOM (Ancient Domains Of Mystery)
Shared: Traditional Roguelike · Dungeon Crawler · Roguelike

Path of Achra
Shared: Roguelike · RPG · Dungeon Crawler

Enter the Gungeon
Shared: Roguelike · Indie · Dungeon Crawler

Hack, Slash, Loot
Shared: Indie · Roguelike · RPG

Torchlight II
Shared: RPG · Dungeon Crawler · Loot

Crypt of the NecroDancer
Shared: Roguelike · Indie · Dungeon Crawler

Dungreed
Shared: Roguelike · Indie · Dungeon Crawler

Rogue Fable III
Shared: RPG · Roguelike · Traditional Roguelike