Kinopio - Thinking canvas for mind mapping, brainstorming, and moodboards
Kanboard - Kanboard is a free and open source Kanban project management software.
ScatterNote - A note-taking app for networked thought
Excalidraw - Excalidraw is a whiteboard tool that lets you easily sketch diagrams that have a hand-drawn feel to them.
Birabo - An effortless collaboration tool for teams
ScrumDesk - ScrumDesk is an online scrum project management tool for small or medium size agile teams which apply Scrum or Kanban.