Freeplane - Freeplane is a powerful and free software for building mind maps.
Source Wireframe Kit - Library of 537 blocks for desktop and mobile prototyping
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.
Form Wireframe Kit by InVision - A free wireframe kit from InVision
vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.
iOS Wireframing UX Kit - An easy, speedy way to wireframe for iOS