Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.
Stormboard - Stormboard empowers data-driven companies to turn their unstructured whiteboards into data-rich collaborative workspaces; enabling data-driven decisions and efficient processes — often eliminating the need for meetings entirely.
GitJournal - Manage your Notes from any Git Repo.
Miro - Scalable, secure, cross-device and enterprise-ready team collaboration tool for distributed teams. Join 2M+ users & 8000+ teams from around the world.
Quillnote - Take beautiful markdown notes and stay organized with task lists.
Mural - MURAL is a visual collaboration workspace for modern teams.