Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.
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.
Perfect Wiki - Build and organize your knowledge base of company resources without switching between workspaces
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Pages by Process Street - Pages is a free-for-everyone knowledge base from Process Street.Try it out!
Slack - A messaging app for teams who see through the Earth!