2008 · 非游戏书籍（但与角色扮演游戏相关）
Game System License
A publishing license for third-party products compatible with the fourth edition of a fantasy role-playing game. It grants access to a System Reference Document containing approved trademarks, terms, and short phrases, but no game rules, along with a required compatibility logo. The license may be updated by the rights holder, with changes applying to all licensees, and assigns certain legal costs to licensees in the event of litigation.
基于属性/数值（STR、CON、PER 等）骰子（主要为 d20）等级制（获得经验值并升级）
免费，支持网页、Android 和 iOS
用 Ludoya 玩 Game System License
游戏信息（人数、游戏时长、年龄、制作人员）来自 BoardGameGeek。