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.
Document360 - Self-service knowledge base software focused on SaaS Products & Enterprise Software Projects.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
ProProfs Knowledge Base - ProProfs Knowledge Base is a cutting-edge knowledge management software that assists businesses to reduces support tickets by self-help and create online manuals, guides, wikis, documentation, FAQs and more.
Slack - A messaging app for teams who see through the Earth!
Onna - Onna centralizes organizations' most common information platforms like Confluence, Slack, Gmail, Drive, and Dropbox.