Explain Everything - Explain Everything is an easy-to-use design, screencasting, and interactive whiteboard tool that...
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.
Microsoft Whiteboard - The canvas where ideas, content, & people come together.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Conceptboard - Instant Whiteboards for Teams & Projects
Slack - A messaging app for teams who see through the Earth!