A quick guide to the rules is also available, which describes very roughly how Yags works, though not in enough detail to actually know how to play.
Below are a number of settings for Yags.
Core Rules
The core rules cover all aspects of the system across all genres, but are setting agnostic. Currently, they are mostly geared towards the fantasy/historical genre, due to campaigns using Yags being of this kind.
Bestiary (PDF): Information about animals and monsters.
Campaign (PDF): Covers skill progression, study, learning and experience awards. Anything to do with the long term campaign.
Characters (PDF): Generic character design rules for Yags, which allows characters to be built for a wide variety of settings, times and genres. Includes lists of skills and advantages available to characters in realistic settings.
Combat (PDF): Basic core rules for the Yags combat system, aiming for a gritty-cinematic style of play. Includes rules for melee, unarmed combat, missile combat and modern firearms. Rules for getting wounded, and getting healed are also included.
Core (PDF): Basic core rules for Yags, describing how the underlaying mechanics work.
Equipment (PDF): Full equipment lists.
Articles
The following short articles describe certain aspects of the rules in detail. Generally, they expand upon particular skills (such as computer hacking) or facet of the game (e.g. vehicle combat) than is suitable in the core rules. Some articles are collected together elsewhere in genre supplements.
Computers (PDF): Rules for using and abusing computers.
Drugs and Medicine: Rules for using and abusing drugs, including medicines and poisons, as well as more obscure drugs. It aims to cover everything from medieval herbs to modern and futuristic medicines.
Environment (PDF): How to survive in harsh environments, or 101 ways to die a horrible and painful death. This article looks at extremes of environment, and how they are modelled in Yags.
Missiles (PDF): Rules guided missiles and other munitions.
Perception (PDF): Rules on noticing things and hiding from other people. The rules here range from reasonably simple through to very complex.
Modern and Science Fiction
Modern and futuristic settings tend to use the same sort of rules - combat tends to be focused on firearms, with plenty of 'high tech' skills in the sciences and technical areas.
Modern Characters (PDF): Creating characters for Modern and SF campaign settings. Includes new skills and advantages for a modern/future campaign.
Yags Modern (PDF): Rules for covering modern and futuristic worlds.
Rules for GDW's Traveller setting are also available, and are basically a specific version of the Modern rules.
Yags Traveller (PDF): Character creation rules for Yags in a Traveller campaign. Also included are skills, techniques and equipment lists.
Yags Traveller Equipment (PDF): Equipment lists for Yags Traveller at Tech Level 12.
Habisfern
Habisfern is an original fantasy campaign setting which has used Yags exclusively from the start. Yags has been designed principally to run Habisfern campaigns.
Habisfern Characters (PDF): Creating characters for the Habisfern campaign.
Habisfern Magic (PDF): Magic in the world of Habisfern, describing how it is used and the background behind it.
Merchants (PDF): On merchants, trade and goods. What is sold, where it is sold, who it is sold to, and what things are used for.