KeepNote
Backup & Sync
Desktop
KeepNote is a versatile note-taking application designed for organizing information in a hierarchical structure. Available on Windows, Linux, and macOS X, it features robust organization tools, including a tree-like outline, wiki-like linking, and support for embedded files and images. Although discontinued, its local storage and rich features make it a compelling tool for detailed note-taking and research.
Open Source
Excellent hierarchical organization for complex information.