So you might like to build fantasy worlds. For creative writing, collaborative stories, for games or for fun.
Here are 5 tools to help you out
1) Medieval Fantasy City by Watabou
Create beautiful city maps, and toggle settings such as settlement features, map size and names
2) Fantasy Calendar
Fantasy Calendar lets you create your own calendar with control over days of the week, moon cycles and festivals. There are presets such as the Gregorian Calendar, Middle Earth hobbits calendar or a random one
3) Azgaar's Fantasy Map Generator
This monster of a tool generates fantasy countries and continents. Choose views of cultures, biomes or military and customize pretty much everything.
4) Landmarks from Oh My Games Master
For something smaller scale try landmarks. create rivers, unholy tombs, ghost towers and escarpments from a long list of areas such as City, Plateau and Wetland
5) RanGen for Everything Else
RanGen has many tools for narratives and writing prompts. Countries, plants, love interests and plot devices await.
There are also regular writing challenges if you want to join a writing community.
Hope you find some inspiration for making your own worlds!