Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.
Linked Ideas - A macOS/iOS apps to treat ideas as links of concepts.
Wondershare PDFelement - All-in-one PDF editor
Freeplane - Freeplane is a powerful and free software for building mind maps.
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.
vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.