Apps to Customizable Interface

Songbird was a feature-rich, open-source media player and web browser aimed at music enthusiasts. It offered a unique blend of music discovery, management, and playback functionalities, with extensive customization options through add-ons. Key features included music library management, playlist creation, syncing capabilities for various devices, and integrated web browsing for exploring music-related content.

Mozilla Firefox is a powerful, open-source web browser developed by the not-for-profit Mozilla Foundation. Known for its strong focus on user privacy and customization, Firefox offers a fast and secure browsing experience across multiple platforms, supported by a vast ecosystem of extensions.

VLC Media Player is a free and open-source cross-platform multimedia player that plays most multimedia files as well as DVDs, Audio CDs, VCDs, and various streaming protocols. Known for its robust format support and stability, VLC is a favorite for playing virtually any media file without the need for external codecs.

Calligra Stage, formerly known as KPresenter, is a free and open-source presentation software designed for creating compelling slideshows with a focus on flexibility and compatibility.

Noise is a sleek and efficient GTK3 audio player designed for managing and enjoying your music library. It prioritizes speed and a clean interface, offering essential features for music enthusiasts who value performance and simplicity.

Eric is a powerful, feature-rich integrated development environment (IDE) primarily designed for Python and Ruby development. Written in Python, it offers extensive capabilities for code editing, debugging, project management, and more, making it suitable for developers of all levels.

Scratch is a powerful yet lightweight text editor designed for developers and anyone working with code or plain text. It offers automatic saving, syntax highlighting, and a range of features to boost productivity, all within a customizable and extensible interface.

LazPaint is a lightweight, portable raster image editor designed for simplicity while offering essential features like layers and various photo effects. It aims to be an accessible alternative to more complex software, making image editing approachable for users seeking a less overwhelming experience.

Denemo is a robust free software graphical user interface (GUI) designed for efficient music notation, primarily acting as a front-end for the powerful GNU LilyPond music engraver. It allows musicians and composers to create high-quality musical scores.

musikCube is a lightweight, partially open-source terminal-based audio player designed for managing and playing large music libraries efficiently. It offers advanced features like smart playlists, plugin support, and internet radio streaming.

Open Atrium is a powerful open-source collaboration and project management platform built on Drupal. It provides a modular framework to create customized intranets, team sites, and project workspaces, facilitating communication, document sharing, task management, and more within organizations.

Geeqie is a blazingly fast and extremely customizable Gtk+ based image viewer designed for Unix-like operating systems. It excels at efficient photo browsing, organization, and basic editing, making it an ideal tool for photographers and anyone dealing with large image collections.

Enlightenment is a highly customizable and lightweight window manager and desktop environment. It's known for its performance efficiency and aesthetic flexibility, offering a modular platform for users seeking a departure from traditional desktop experiences.

Nightingale is a highly customizable cross-platform audio player with a focus on extensibility, featuring a beautiful interface, a wide array of supported formats, and tools like media library management, podcast playback, and integrated web browsing.

LineageOS is a free and open-source Android-based operating system designed for smartphones and tablets, offering enhanced privacy, security, and customization options over standard manufacturer ROMs.

gmusicbrowser is a highly customizable, open-source music player and library manager designed for users with large audio collections. It offers a range of advanced features including intelligent playlists, flexible tagging, and extensive interface customization, making it a powerful alternative to mainstream music players.

Bloodshed Dev-C++ was a robust free IDE for C and C++ programming in Windows. It provided a complete development environment with compiler, debugger, and editor, commonly used by students and enthusiasts.

Karbon is a free and open-source vector graphics editor, part of the Calligra Suite. It enables artists and designers to create scalable vector artwork, illustrations, and graphics, supporting various features like layers, vector tracing, and export options.

GIMPshop was a discontinued modification of the free and open-source GIMP image editor, designed to provide a user interface and workflow closer to Adobe Photoshop for users transitioning between the two programs. It aimed to reduce the learning curve for Photoshop users exploring open-source alternatives.

UMPlayer is a free and open-source cross-platform media player that boasts a built-in search for YouTube and Shoutcast radio, offering a wide range of supported formats and features like automatic subtitle downloads and customizable playback options.

MuseScore is a powerful and free open-source scorewriter software enabling musicians to create, edit, and print sheet music. It offers a user-friendly interface with comprehensive tools for composition, arrangement, and playback across Windows, macOS, and Linux platforms.

DeaDBeeF is a lightweight and highly customizable audio player for Linux and other Unix-like systems. It supports a wide range of audio formats and offers advanced features like audio conversion, plugin extensibility, and comprehensive playlist management, making it a powerful choice for audiophiles and everyday users alike.

TiddlyWiki is an innovative open-source, single-file, non-linear personal web notebook.

Lightning is a comprehensive calendar and task management add-on for Mozilla Thunderbird and Seamonkey, designed to integrate seamlessly with email. It offers robust features for scheduling, task tracking, and synchronization with various online calendar services, enhancing productivity directly within your email client.

FBReader is a versatile and free ebook reader application supporting multiple formats including ePub, Kindle azw3, and fb2. It offers a customizable reading experience across different platforms with features like library management, synchronization, and text-to-speech.

SeaMonkey is a free and open-source internet suite developed by the Mozilla Foundation. It bundles a web browser, email and newsgroup client, HTML editor, and IRC chat client into a single application, offering a comprehensive online experience.

Midnight Commander is a powerful, console-based file manager offering a two-panel interface for efficient file handling. Licensed under the GNU GPL, it's a free software tool for managing files and performing operations like copying, moving, and deleting with ease.

Kubuntu is an official variant of the Ubuntu operating system that replaces the GNOME desktop environment with the elegant and highly customizable KDE Plasma Desktop. It provides a familiar yet powerful computing experience, blending Ubuntu's stability with the visual appeal and extensive features of the KDE ecosystem.

Double Commander is a free and open-source cross-platform file manager with a classic dual-panel interface. It provides essential file management operations alongside advanced features like batch renaming, folder synchronization, and built-in viewers and editors, making it a comprehensive tool for efficiently organizing and manipulating files across various operating systems.

StarDict is a powerful, free, open-source dictionary application that provides swift access to a vast collection of dictionary files. It supports various dictionary formats and offers offline functionality, making it an essential tool for language learners and researchers.