TreeSheets combines spreadsheet tools, mind mappers, outliners, personal information managers, text editors and small database utilities into an all-in-one office application.
Evernote is a note management application that offers you a single place for the organization, easy input and quick retrieval of all types of notes and clippings.
Outlook CalDav Synchronizer is a free Outlook Plugin that synchronizes events, tasks, and contacts between Outlook and Google, SOGo, Nextcloud, Horde, or any CalDAV or CardDAV server.
CalendarTask (formerly DesktopCal Desktop Calendar) helps you manage appointments, to-do lists, schedules, and more without blocking access to your desktop icons.
Cherrytree for Windows, Mac, and Linux is a free hierarchical note-taking application featuring rich text and syntax highlighting, storing data in a single XML or SQLite file. Zero-dependency portable version is also available.
VOVSOFT Tree Notes is an application for taking hierarchical notes designed to improve organizational efficiency and streamline information management.
Stickies Portable will help you minimize the clutter of physical Post-It notes on your monitor(s). Providing a digital alternative allows for better organization and easier access to important reminders and notes directly on your computer screen. Also available as an installer.
RedNotebook Portable provides a modern journal with calendar navigation, customizable templates, export functionality, word clouds, and more. Available as an installer.