Open source alternatives to Dungeons & Dragons

Dungeons & Dragons (D&D) is easily the most widely played roleplaying game in most places (except for Call of Cthuhu in Japan) however there are thousands of alternatives.

In this post I will highlight a few open gaming alternatives, all highly rated (either the game itself, if fully available, or if just and SRD the commercial game it is derived from is highly rated).

  • Fate
  • Open Basic (d100% / Basic Role-Playing)
  • Dungeon World (Powered by the Apocalypse)
  • Blades in the Dark (Forged in the Dark)
  • Gumshoe System

Open gaming

Open gaming refers to rule sets, or more correctly the textual expression of rule sets, that are released under and open licence.

An early, gaming-specific licence, was the Open Gaming Licence, pioneered by Wizards of the Coast for Dungeons & Dragons, which led to a revival of the industry and a boom in "d20" compatible products.

More modern systems are often released under a general licence such as Creative Commons Attribution (CC-BY), although some have their own variations.

Generally what is released is not one of the game settings themselves, but a System Reference Document (SRD), which contains the cores rules from one, or more, of the settings.

By itself the SRD may not be usable as a game system, e.g. the Dungeons & Dragons SRD only includes one background and one feat, but as a reference to allow compatible products to be created.


System reference
Licence OGL or CC-BY 3.0

Derived from an earlier lightweight, multi-genre, open gaming system, Fudge, this system is characterised by it's Fudge/Fate dice, which are a d6 cube, but with two plus (+) sides, two minus (-) sides, and two blank sides. Effectively the system uses 4d3. I have previously done a more indepth review of Fate mechanics.

The Fate family has enjoyed significant success, including several popular settings such as the Dresden Files, Diaspora, Spirit of the Century, and Fate of Cthulhu. The full rulebook is quite lengthy, but the system itself is simple with the Fate Accellerated version only 40 pages long.

The open gaming releases of Fate are fully developed games, not just reference documents, contaning the full text of the core system. The are genre-agnostic, so can be used for running fantasy, horror, historical, modern, or sci-fi games. There are no classes or levels, although there is some niche protection using the default skill pyramids (you can only be the best at one thing).

The accelerated version uses approaches (rather than skills) and aspects (narrative triggers). The core replaces approaches with more traditional skills, and adds stunts, and then game system includes guidance for further customisation for the type of game / genre.

The system is quite narrative, powered by plot points, with several options for players to earn themselves, including narrative compels (of aspects) and conceding a contest. Contest resolution includes a band of succeed-at-a-cost results (rather than always win/lose).

On the flipside, like many narrative games, there is not a lot of strategic elements.

If you want a lightweight, multi-genre system, with the fully-fledged rules available for free, then have a look at Fate.

Open Basic (d100% / Basic Role-Playing)

System reference
Licence OGL

Open Basic is the most simplest version of the d100% rules, only 10 pages long, and contains the essential core of the Basic Role-Playing (BRP) system, using simple percentile based skills plus a set of seven attibutes. It has only a dozen skills, medieval era weapons and armor, and no magic system.

BRP is used across many games, including Chaosium's popular Call of Cthulhu and Pendragon. Most BRP games are not open, but they share the same mechanics so are compatible. You can find a long list at BRP Central

Legend: The OGL rules originated from RuneQuest, an early roleplaying game from Chaosium, published by a series of companies until an Open Gaming Licence version was published by Mongoose:

Since then, the trademark has returned to the original publishers, Chaosium, and the Mongoose version renamed Legend.

OpenQuest is a cleanup of the Legend rules, but still quite long at 250+ pages. It has a number of simplifications (e.g. treating doubles on the percentile dice, which is close to 1/10th, as criticals) and streamlines the earlier variations

Both Legend & OpenQuest are much more complete games, although both are still medieval fantasy focussed (with magic systems).

The system is straight forward, so if you have a Persuasion skill of 70% it means you have a 70% chance to succeed under normal circumstances. Difficulty applies a modifier of up to +/- 50% (another variation halves, or more, the skill). Criticals are generally 1/10th of the relevant skill.

While character creation can be involved, most of the longer games have some ready made templates, and the use of percentile skills is straight forward and easy to understand. There are no classes or levels, and any character can pick up any skill. The structure is a fairly standard skills based approach, with the open versions being a good introduction to the BRP family.

Dungeon World (Powered by the Apocalypse)

System reference
Licence CC-BY 3.0

Ths fantasy version using the Powered by the Apocalypse (PbtA) engine has opened up the system with a Creative Commons licence. The fully playable text of Dungeon World, not just a reference document, is available.

Some popular (but non-open) systems using PbtA, including the original Apocalypse World, Masks: A New Generation, and Monsterhearts.

In Powered by the Apocalypse, all rolls are made by players, roll 2d6 plus the relevant attribute modifier (which could be negative). You need a 10+ for complete success, with 7-9 being success-at-a-cost (basicaly, the opposition also succeeds). Failures, 6 or below, earn experience.

Characters use class-based playbooks (e.g. Fighter, Wizard, Druid, etc), which each have special moves, in addition to the standard moves (although the game is not level based). Recovery, downtime, advancement, and even death, also use the same move structure, with success-at-a-cost being a large focus of the game.

All rolls are made by players, so even when the gamemaster has narrated a dangerous threat, such as an attacking undead, they do not make a roll for the threat, but the player rolls for a Defy Danger move.

The moves (actions) in the system are all described in a narrative style, so easy to understand. There are about 20-30 pages of core rules and moves, and about 5 or more extra pages for each class, plus a bunch more for gamemasters with monsters and such.

There are attributes, and different special powers, but no skill or other ratings as such, as the system is very much focussed around the specific moves.

However, each move has slightly different rules, so you probably need to keep a copy to reference during play. Separate actual playbooks per character class can help this.

Character classes also have built in hooks for the other characters, and the system overall is very narrative — although some players may prefer their narrative a little more freeform, rather than tied to specific rules (for downtime, relationships, and even dying).

If you are looking for a more narrative alternative to D&D, have a look at Dungeon World, or one of the variants for other genres.

Blades in the Dark (Forged in the Dark)

System reference
Licence CC-BY 3.0

Another narrative system that was a Kickstarter success, which has spawned a range of Forged in the Dark derivatives, including the sci-fi setting Scum & Villany, and an open gaming cyberpunk CBR+PNK game.

The original game has an extensively developed city setting of Doskvol, which some players or gamemasters might find daunting with the amount of lore. The setting is also very dark, with the players taking the role of a crew of thieves, assassins, religious extremists, or at best resistance fighters, although some of the derivatives may allow more heroic themes.

The basic game system is a fairly simply dice pool system, with only 12 skills, using plain d6s, where you are trying to roll one or more 6, although the system reference document is still 100 pages long.

If you don't get any sixes, then if the highest dice is 4 or 5 you get a partial success. Dice pools are small (1-4 dice), but even with a single die you chance of success (possibly at a cost) is still 50%.

There are good narrative elements, with being taken out of a scene generally resulting in coming back with a trauma (rather than just death), and the partial success / success-at-a-cost results give a lot of flexibility in the range of outcomes from an action.

There are mechanics for starting jobs in-situ, rolling for your starting position, with flashback options for specifics, rather than extensive pre-planning. Equipment is handled similar, choosing your load at the begining (heavy or light), but then pickinig specific items as needed.

There are also extensive downtime rules for growing your crew's territory and reputation, and for characters indulging in their vices (gambling, addiction, etc). The game is also more focused around the legacy of the crew than individuals, as characters may often be out due to injury, incarceration, or overindulging their vices, and players are encouraged to play a different junior member the crew. Characters are also likely to die, or retire from trauma, with players continuing with a replacement.

If you like dark and gritty, with extensive world building, then these is a good set of systems. (I prefer heroic games, although one of the sci-fi variants might be okay.)

Gumshoe System

System reference
Licence OGL or CC-BY 3.0

This system focuses on investigation and mystery, designed to handle situations that are often difficult in roleplaying games. The open gaming release is a system reference document, for developers, and not really a complete game, but does provide an overview of the rules.

Some highly rated commerical games using the Gumshoe system include Trail of Cthulhu (focussed more on the investgation aspects rather than the horror aspects) and Night's Black Agents.

Core clues are automatically found by the characters with the relevant skills, with the focus more on interpretation than whether you find the clue or not. This avoids the narrative issue or failing a roll when searching for clues. Additional clues or addtion detail can be found by spending limited points from these skill areas.

Action resolution, outside of investigation, is a simple d6 roll, with players spending skill points for extra effort. A simple difficulty will require 4+ (or 3+), with more complex actions requiring 7+ or even 8+.

While the system is narrative focussed, and has simple mechanics, the list of skills is quite long (60+ investigative, 25+ general), and the rules about how to run conlicts are a bit complicated with a lot of special conditions.

If you have ever found yourself disappointed, or frustrated, by how regular roleplaying games handle investigation scenarios, then consider having a look at one of the Gumshoe games.

Dungeons & Dragons

System reference
Licence OGL

Yes, Dungeons & Dragons was actually one of the earlier open gaming systems, or at least made it popular when they created the Open Gaming Licence (inspired partly by eariler open systems, such as Fudge, which evolved into Fate).

D&D 3rd edition / 3.5 has a system reference document (not the full rules) available under the OGL, which led to an explosion of compatible "d20" products (with a licencing rules for the logo).

The effort slowed during 4th edition, but is once again fully supported in 5th edition. The SRD is still only a reference - it includes creation rules, only a single background, feat, and subclass (per class), and limited spells and monsters.

This is useful for developing compatible products, but not as rules.

However, the basic rules are aso available for free, but still copyrighted, download, and a slightly different set freely available online at DnD Beyond.

D&D is certainly the most well known system, and 5th edition is highly rated with many improvements over earlier versions, even if Basic Role-Playing, Powered by the Apocalypse, Forged in the Dark, and Gumshoe based systems slightly outrank it.

Other open gaming systems

Finally, if the above is not enough, here are some brief mentions of a few other open gaming systems:

Eclipse Phase: CC-BY-NC-SA 3.0, - Near future transhuman sci-fi game, featuring uplifted animals, artificial intelligence, robot bodies, and a touch of strange alien technology.

This is a full game (not just an SRD). The system is percential (d100%) based, with the different morphs (bodies) giving pools of points that can be used to enhance different actions.

Ironsworn:: CC-BY-NC-SA 3.0, - Heroic viking sagas, where you swear iron vows that you will complete. Heavily influenced by Dungeon World, with character making moves, not just for actions but also downtime and advancement, but with a different dice rolling mechanic.

Ironsworn also includes extensive random oracles to allow solo play or co-operative (GM-less) play, for collaborative storytelling. The full text is available for free under a creative commons no commerical licence. (And there is a basic SRD available under a less restrictive CC-BY licence).

If you are interested in some solo play, or co-operative GM-less play, then it is worth taking a look at, and then if you like it consider supporting the developer.

There is also a sci-fi variant, Starforged.

13th Age:, OGL, - d20-based fantasy gaming system, with classes and levels, with some aspects simplified, and some narrative focus with each character having their own "one unique thing".

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