Document360 - Self-service knowledge base software focused on SaaS Products & Enterprise Software Projects.
Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.
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.
Joplin - Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.
Onna - Onna centralizes organizations' most common information platforms like Confluence, Slack, Gmail, Drive, and Dropbox.
Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.