To address the lack of documented best practices in the development of digital educational games, we have previously proposed a reference software architecture. One of its components is the rule system specifying learning and gameplay content. It contains quest, player character, non-player character, environment, and item rules. Documented content design patterns can assist in the authoring of such rules. We report on four studies that have collected quest, character, environment, and item design patterns by analysing a variety of media. We present a selection of the results, and discuss how the patterns can be used in designing educational game content.