Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Walling for Windows - Visual walls for your ideas and projects. Now on Windows.
Lanes - Superpower your productivity.
Microsoft Whiteboard - The canvas where ideas, content, & people come together.
Asana Timeline - Visualize your project plan so you can hit your deadlines.
Milanote - Milanote is a note taking app for creative work.