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.
UserGuiding - User onboarding made easy, for less. Create product walkthroughs in a couple of clicks, without breaking the bank.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Usetiful - Fight user churn with great user onboarding. Interactive product tours and smart tips significantly improve your user retention.
Slack - A messaging app for teams who see through the Earth!
Userlane - Digital adoption platform with interactive guidance for software applications allowing anyone to understand and master any software from the get-go.