Mac OS X Softwares to To-Do management

Nitro was a free, open-source task management application designed to help users organize their daily tasks and boost productivity. It featured a clean interface and supported various integrations for a streamlined workflow.

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.

Things is a highly acclaimed task manager designed for macOS, iPadOS, and iOS platforms. It offers a clean, intuitive interface to help users capture, organize, and complete their tasks and projects effectively. Praised for its minimalist design and powerful features, Things aims to make personal productivity effortless and enjoyable.