Realm Works is described as 'database software and worldbuilding tool for roleplaying games'. There are five games similar to Realm Works for Online / Web-based, Mac, Windows and Linux. The best alternative is LegendKeeper. It's not free, so if you're looking for a free alternative, you could try Notebook.ai or Scabard. Other Realm Works like games are YARPS (Paid) and Toyhouse (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.
YARPS is a smart web application for creating and managing vivid worlds, planning and documenting your stories, enhancing your role-playing with portraits, interactive maps and music and for trading RPG content.