Linked Ideas - A macOS/iOS apps to treat ideas as links of concepts.
Xmind - Xmind is a brainstorming and mind mapping application.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.
SuperNotecard - Introducing SuperNotecard. SuperNotecard is an online writing tool that features virtual notecards to help arrange facts or scenes, track details, organize paragraphs, and clarify your composition process.