Scrivener - Scrivener is a content-generation tool for composing and structuring documents.
Freeplane - Freeplane is a powerful and free software for building mind maps.
Manuskript - Open-source tool for writers.
Linked Ideas - A macOS/iOS apps to treat ideas as links of concepts.
FocusWriter - FocusWriter is a fullscreen, distraction-free word processor designed to immerse you as much as...
vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.