Mac OS X Softwares to Cross-platform

LibreOffice Base is a robust desktop database application designed to streamline the process of creating, managing, and querying databases. It provides an intuitive interface suitable for both beginners and experienced users, facilitating easy data handling and reporting.

Xamarin Studio is a comprehensive IDE designed for building cross-platform applications for iOS and Android using C#. It enables developers to write native user interfaces and share significant code across platforms.

Smuxi is a feature-rich, cross-platform IRC client designed with productivity and usability in mind. Inspired by the command-line power of Irssi, it provides a graphical interface for seamless communication across multiple networks including IRC, XMPP, and Twitter.

Nextcloud is an open-source, self-hosted platform for file synchronization, sharing, and collaboration. It provides a private alternative to commercial cloud storage services, offering a comprehensive suite of tools including file management, calendar, contacts, and notes, all under your control.

MongoDB is a leading free and open-source NoSQL database, designed for modern applications. It offers a flexible document data model, high performance, and seamless scalability, making it ideal for various use cases from mobile to enterprise applications.

Lazarus is a powerful, free, and open-source visual IDE for rapid application development with Free Pascal. It provides a Delphi-like experience for creating cross-platform native applications across various operating systems.

Affinity Photo is a professional raster graphics editor designed for photographers and digital artists on macOS and Windows. It offers powerful tools for image editing, retouching, and complex layer manipulation without a subscription model, making it a compelling alternative to industry-standard software.

LaTeX is a high-quality typesetting system widely used for producing scientific, technical, and academic documents. It offers precise control over formatting, complex mathematical expressions, references, and document structure, making it ideal for professional publishing.

muCommander is a versatile, open-source file manager designed for productivity across various operating systems. It offers a dual-pane interface for efficient file operations, built-in support for network protocols like FTP and SSH, and extensive customization options, making it a powerful tool for both casual users and power users who need advanced file management capabilities.

MonoDevelop, now integrated into Xamarin Studio, is a versatile open-source integrated development environment supporting multiple languages and platforms, including C#, F#, .NET, and web development with extensive debugging capabilities.

Darktable is a powerful, open-source and free photography workflow application and raw developer, offering professional-grade tools for managing and editing digital negatives. It's a non-destructive editor designed by photographers for photographers.

Firefox PDF Viewer (PDF.js) is an open-source, web standards-based PDF viewer embedded directly within the Firefox browser. It allows users to view PDF documents seamlessly without the need for external software or plugins, enhancing browser-based document handling and accessibility.

QuiteRSS is a free, open-source, cross-platform RSS/Atom news feed reader featuring an integrated web browser, filtering options, notifications, and support for multiple languages. It's designed for efficient news consumption and organization.

Mathematica is a comprehensive software suite for technical computing, widely used in scientific, engineering, and mathematical fields for its powerful symbolic and numerical computation capabilities.

R is a powerful open-source language and environment for statistical computing, graphics, and data analysis. Widely used by statisticians and data miners for developing statistical software and data analysis.

UltraEdit is a powerful and versatile text, hex, and code editor designed for Windows, Mac, and Linux. It offers a comprehensive feature set for developers, programmers, web designers, and general users working with text files, code, and binary data.

OpenGL is the industry standard API for developing high-performance, cross-platform 2D and 3D graphics applications, widely utilized in gaming, simulation, CAD, and visualization.

C# is a versatile, modern, object-oriented programming language from Microsoft. It's widely used for developing Windows applications, web services, mobile apps, and games, offering a balance of power and ease of use.

Duplicati is a robust, free, and open-source backup client that securely stores encrypted, compressed, and incrementally updated backups on various cloud storage services, remote servers, or local drives. It's designed for both technical users and those who prefer a guided configuration.

Electron is an open-source framework that allows developers to build desktop applications using familiar web technologies like JavaScript, HTML, and CSS. It combines the Chromium rendering engine and the Node.js runtime, enabling the creation of cross-platform desktop GUI applications with web development skills.

Node.js is an open-source, cross-platform JavaScript runtime environment designed for building scalable network applications and server-side applications. It allows developers to use JavaScript for both frontend and backend development, fostering full-stack JavaScript development.

PostgreSQL is a robust, open-source object-relational database system renowned for its extensibility, standards compliance, and advanced features. It is highly regarded for its reliability, data integrity, and performance, making it a popular choice for critical enterprise applications and data warehousing.

Qt is a powerful cross-platform framework designed for developing native applications with intuitive user interfaces. It enables developers to write code once and deploy it across multiple operating systems including desktop, mobile, and embedded systems. With a focus on productivity and performance, Qt provides a comprehensive set of tools and libraries for building robust and engaging applications.

SQLite is a widely adopted open-source embeddable database engine, known for its serverless architecture, zero configuration, and small footprint.

Ruby is a dynamic, open-source programming language known for its elegant syntax and focus on developer productivity. It's widely used for web development, scripting, and rapid prototyping.

C is a foundational, imperative programming language renowned for its efficiency and low-level access. It serves as a bedrock for systems programming, operating systems, and performance-critical applications, providing direct control over hardware through features like manual memory management.

Jitsi is a free and open-source suite of secure, flexible communication tools. It offers multi-platform support for voice (VoIP), video conferencing, and instant messaging, emphasizing privacy and ease of use with no account required to start a meeting.

MySQL Community Edition is the widely adopted open-source relational database management system (RDBMS). It provides a robust, high-performance, and scalable solution for various applications, from small web projects to large-scale enterprise systems. Its reliability and rich feature set have made it a cornerstone of modern data management.

GNU Emacs is a highly extensible and customizable text editor, renowed for its powerful features and ability to serve as a complete development environment. It is based on the Emacs Lisp programming language, allowing for deep customization and a vast ecosystem of packages.

Apache CouchDB is a schema-free NoSQL database built for reliability and scalability, particularly in offline-first applications. It emphasizes ease of use and fault tolerance by using a peer-based distribution model and a robust replication mechanism. Its HTTP-based API and JSON document format make it developer-friendly.