Mac OS X Softwares to Extensible by Plugins/Extensions

LibreOffice Calc is a powerful and free spreadsheet application, part of the LibreOffice suite. It offers extensive functionality for creating, editing, and managing spreadsheets, including complex calculations, data analysis, charting, and compatibility with various file formats, including Microsoft Excel.

SketchUp is a powerful 3D modeling software widely used for architectural design, interior design, mechanical engineering, and more. It offers an intuitive interface and a vast library of pre-made models, making it accessible for both beginners and professionals.

Safari is Apple's native web browser, deeply integrated into macOS and iOS. Known for its speed, energy efficiency, and strong focus on user privacy, it provides a seamless browsing experience across Apple devices.

Iridium Browser is a security-focused web browser built upon the Chromium codebase. It prioritizes user privacy by significantly reducing data transmission to Google and other servers, while incorporating enhanced security features and utilizing the latest secure technologies for a safer browsing experience.

ReText is a straightforward yet effective text editor designed primarily for authoring documents in Markdown and reStructuredText. It provides essential features like live preview and syntax highlighting, making it a suitable choice for writers and developers who prefer lightweight, plain text formats.

BBEdit is a powerful and robust text, code, and markup editor for macOS. Renowned for its stability and feature set tailored for developers and writers, it offers advanced search and replace, syntax highlighting, and integration with developer tools.

Deluge is a free, open-source BitTorrent client offering a lightweight and cross-platform solution for downloading and sharing files. Known for its extensibility through plugins, it provides users with a customizable and efficient torrenting experience.

Launchy is a discontinued yet highly efficient open-source keystroke application launcher for Windows, macOS, and Linux. It allows users to quickly open programs, documents, and perform searches by typing their names, significantly speeding up workflow.

Atom is a highly customizable and extensible open-source text editor developed by GitHub. Built on Electron, it provides a modern, hackable platform for developers, offering robust features like syntax highlighting, Git integration, and a vast ecosystem of packages to enhance productivity and tailor the editing experience to individual needs.

NetBeans is a free and open-source Integrated Development Environment (IDE) specifically designed for enterprise-level Java development, supporting a wide array of other languages and technologies, including PHP, C++, JavaScript, HTML, and CSS. It provides comprehensive tools for coding, debugging, testing, and deploying applications.

Blender is a comprehensive, free, and open-source 3D creation suite supporting the entirety of the 3D pipeline—modeling, rigging, animation, simulation, rendering, compositing and motion tracking, video editing, and 2D animation pipeline.

Vim is an advanced, highly configurable text editor designed for efficiency, particularly favored by developers. Operating primarily in the terminal, it offers powerful editing capabilities through keyboard commands, syntax highlighting, and extensive plugin support, making it a cornerstone tool for programming and advanced text manipulation.

Eclipse is a powerful, open-source Integrated Development Environment (IDE) widely used for Java development, but also supporting a variety of other programming languages through its extensive plugin ecosystem. It provides a robust set of tools for coding, debugging, testing, and deployment.

Kodi is a powerful, free, and open-source media player software designed to transform your device into a comprehensive home theater PC. It provides a stunning interface optimized for large screens, allowing you to manage and play virtually all popular types of digital media.

KeePass is a free, open-source, and highly secure password manager. It stores your passwords in a strong encrypted database, accessible with a single master password or key file. Offering robust security features and extensive customization options, KeePass is an excellent choice for users prioritizing data privacy and control.

Opera is a feature-rich web browser known for its performance, built-in privacy tools like a free VPN and ad blocker, and unique features such as workspaces and messaging app integration. It provides a fast, secure, and personalized browsing experience across various platforms, including desktop and mobile.

Pidgin is a free and open-source multi-protocol instant messaging client designed to connect users across various chat networks with a single application. It's highly extensible through plugins and supports a wide range of protocols including XMPP, ICQ, and IRC.

Sublime Text is a sophisticated text editor for code, markup, and prose. It's known for its speed, powerful features, and extensive customization options. With features like multiple cursors, GoTo Anything, and a robust plugin ecosystem, it's a favorite among developers and writers alike for boosting productivity and creating a tailored editing environment.

LaunchBar is a powerful and intelligent keystroke-based launcher for macOS. It provides lightning-fast access to your applications, documents, contacts, calendars, bookmarks, and much more, simply by typing a short abbreviation.

Peppermint is a lightweight and native code editor designed exclusively for macOS, offering a clean and fluid interface for developers. It focuses on providing essential features like syntax highlighting, code completion, and built-in tools for a productive coding experience.

Colloquy is more than just a loyalty platform; it's a comprehensive customer engagement and data analytics solution designed to foster deep relationships and drive business growth. It provides tools for managing customer loyalty programs, facilitating direct communication, and deriving actionable insights from customer data.

Picasa was a free photo management and editing software developed by Google. It offered a user-friendly interface for organizing, editing, and sharing digital photos. Although discontinued, it remains a classic tool for many users due to its simplicity and robust feature set for its time.

Adobe Photoshop is the industry-standard professional image editing software. It provides a comprehensive suite of tools for manipulating, retouching, and creating raster graphics. From simple photo adjustments to complex digital art, Photoshop empowers users across various creative disciplines.

Thunderbird is a free, open-source email client developed by the Mozilla Foundation, offering robust features for managing multiple email accounts, integrated chat, and RSS feeds. Known for its extensibility and focus on user privacy and security.

LibreOffice is a powerful, free, and open-source office suite for text editing, spreadsheets, presentations, and more. It's compatible with a wide range of file formats, including Microsoft Office documents, making it a versatile alternative for personal and professional use across various operating systems.

VirtualBox is a powerful x86 and AMD64/Intel64 virtualization product for enterprise as well as home use. As an open-source, freely available software, it allows users to run multiple operating systems simultaneously on a single physical machine. This enables diverse use cases, from software development and testing to creating isolated environments for everyday tasks.