Freeplane - Freeplane is a powerful and free software for building mind maps.
Microbit - BBC's handheld, programmable computer given free to UK kids
Linked Ideas - A macOS/iOS apps to treat ideas as links of concepts.
Novlr - Online word processor and organizer for novel writing.
vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.
Dabble Writer - Writing software for novelists.