Obsidian Portal is described as 'Say Hello to Your New GM Notebook! EASY WIKI BUILDING Build your campaign website with our easy to use wiki. Organize things in a way that makes sense for your game. ANY SYSTEM' and is a World Building Game in the Games category. There are seven games similar to Obsidian Portal for Online / Web-based, Windows, Android and Steam. The best alternative is World Scribe, which is free. Other Obsidian Portal like games are Fantasia Archive (Free, Open Source), LegendKeeper (Paid), Campfire Pro (Paid) and kanka.io (Freemium).
The ultimate toolkit for world-builders. A WIKI FOR WORLDS Use on-the-fly article creation and templates to easily expand your evolving world. AUTO-LINKING The editor recognizes familiar names in your articles and automatically creates links.
ChronoGrapher is an extremely flexible worldbuilding tool for writers, worldbuilders and game masters. It boasts a freeform notetaking wiki, interactive maps, tile map editor, extensive time and history tracking features and much more.