Planview IdeaPlace - Spigit is a software program designed to help CEOs and industry leaders to tap into the creativeness of their employees. It brands itself as an idea management tool. Read more about Spigit.
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.
Brightidea - With over 2 million users worldwide and $15+ billion in recorded business impact, Brightidea is ranked as the #1 Idea Management Platform globally and is the market leader in innovation management.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
ScatterNote - A note-taking app for networked thought
Slack - A messaging app for teams who see through the Earth!