vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.
Platforma - Wireframe library of layouts and UI elements
Freeplane - Freeplane is a powerful and free software for building mind maps.
Contra Wireframe Kit - Open source wireframe kit for design and 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.
Source Wireframe Kit - Library of 537 blocks for desktop and mobile prototyping