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
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Pages by Process Street - Pages is a free-for-everyone knowledge base from Process Street.Try it out!
Influitive - Influitive helps companies increase customer lifetime value and accelerate sales with the power of their own customer advocates. Inspire your customers to stay longer, share their experiences, and attract new business.