Best Free and Open Source Software, and many more

posted by Rianne Schestowitz on Aug 31, 2026

• Dasel - query, modify and transform structured data

  Dasel is a command-line tool for querying, modifying and transforming structured data. It provides a unified syntax for working with JSON, YAML, TOML, XML, CSV, HCL, INI and KDL data.

  The software lets you select and search values, update structured documents and convert data between supported formats. It is designed to work well in shell scripts and pipelines, and can also be used as a Go library.

  This is free and open source software.

• Detox - gray-box end-to-end testing and automation framework

  Detox is a gray-box end-to-end testing and automation framework for mobile applications. It runs tests against Android and iOS applications on devices or simulators and synchronizes test actions with activity inside the application.

  This is free and open source software.

• moonlight – extensible Discord client modification

  Its community catalogue contains more than 100 extensions, which can be installed and configured through the Moonbase interface. Extensions in the official repository are reviewed by the project team and built from source using public GitHub workflows; third-party repositories remain the user’s responsibility.

  Developers can modify Discord through conventional Webpack patches or abstract syntax tree transformations without recompiling moonlight itself. Browser builds are available for Chromium and Firefox, although the project describes browser support as experimental and custom repositories may encounter cross-origin restrictions. Using moonlight contravenes Discord’s Terms of Service, as is the case with other unofficial client modifications.

  This is free and open source software.

• FIPS – OpenGL-based FITS image viewer

  The application is designed around the Flexible Image Transport System (FITS), a format widely used for storing astronomical and other scientific image data. Instead of relying solely on CPU rendering, FIPS takes advantage of GPU hardware for common viewing operations.

  FIPS supports all 2D FITS image formats, although floating-point formats are not supported when using OpenGL 2.1. There is also basic, limited support for FITS image extensions.

  The interface provides the essential controls needed when inspecting FITS data, including zooming, panning and image level adjustment. OpenGL 2.1 and later is supported.

  The project is also available for macOS and Windows, making it useful for researchers and astronomers who work across multiple platforms.

  This is free and open source software.

• bited - bitmap font designer and editor

  bited is a bitmap font designer and editor focused on monochrome Unicode BDF fonts. It provides a graphical environment for creating pixel fonts from scratch as well as importing and modifying existing fonts.

  The interface includes an editor for drawing individual glyphs, a glyph table for working with multiple characters, and a tree for navigating character sets and encodings. Fonts can be previewed with test text while they are being designed.

  This is free and open source software.

• shelter – robust Discord client modification

  It emphasizes resilience by minimizing its dependence on Discord’s frequently changing internal implementation. The modification operates within the web environment and does not require Node.js at runtime, which makes it suitable for both browser-based Discord and compatible desktop wrappers. shelter supplies a plugin system, documented APIs and development tooling intended to make extensions easier to maintain. Official browser extensions are available for Firefox and Edge, while Chromium users can install an unpacked build manually. Its desktop installer supports multiple platforms without requiring root privileges. Community plugins are not continuously audited, so users should evaluate their source and permissions. Client modification also contravenes Discord’s Terms of Service.

  This is free and open source software.

• Laigter – generate lighting maps for 2D game artwork

  Laigter is a graphical texture utility for turning 2D artwork into maps used by dynamic lighting systems in games.

  It analyses a diffuse image and can derive normal, parallax, specular and occlusion maps without requiring the artist to model the sprite in 3D. Adjustable generation settings and a live preview help balance depth and highlights before the maps are exported. Although particularly suited to sprites and other hand-drawn game assets, its preset system and command-line mode also make it practical for repeatable batches. The application is built with Qt and OpenGL and provides a native GUI alongside non-interactive operation.

  This is free and open source software.

• SatX – live 3D satellite and space debris tracker

  SatX is a desktop satellite tracker that visualises artificial satellites and space debris on an interactive 3D globe. It downloads public two-line element data and continuously calculates current orbital positions rather than receiving live telemetry from individual spacecraft.

  Users can filter the catalogue by object type, search by name or NORAD identifier and inspect the satellites nearest to their location. Optional Starlink integration reads the pointing direction from a locally accessible dish and attempts to identify its serving satellite.

  The application is built with Tauri, React, Three.js and satellite.js. It operates locally without a SatX cloud service, although an internet connection is needed to download the orbital catalogue.

  This is free and open source software.

• Xfce4 Notes Plugin - sticky notes for the Xfce desktop

  Xfce4 Notes Plugin provides sticky notes for the Xfce desktop. It offers a quick way to jot down a to-do list, paste a piece of code, record a reminder or keep other short pieces of information readily accessible.

  The software integrates with the Xfce panel, giving you convenient access to your notes from the desktop. Notes are stored locally under the XDG data directory.

  This is free and open source software.

• 5 Useful Free and Open Source Terminal String Styling Libraries

  ANSI escape sequences provide the foundation for this presentation, yet working with them directly can be cumbersome. Developers must consider colour support, terminal capabilities, nested styles, output redirection and user preferences. A well-designed programming interface handles these details while keeping source code readable and avoiding unnecessary overhead.

  The strongest options make it simple to apply foreground and background colours, bold or underlined text and other visual effects. They should also degrade gracefully when styling is disabled or unsupported. Performance matters too, particularly for command-line programs that generate large volumes of output or run frequently as part of automated workflows.

  Choosing the right approach depends on several factors, including programming language, API design, portability, feature set and resource use. Some developers favour minimalism and speed, while others need richer formatting or more sophisticated terminal detection.

  Here’s our verdict captured in a legendary LinuxLinks-style ratings chart. Only free and open source software is eligible for inclusion.

• Kanata - cross-platform keyboard remapper

  Kanata is a cross-platform keyboard remapper. It lets you extensively customise keyboard behaviour, bringing functionality commonly associated with programmable keyboard firmware to ordinary keyboards, including laptop keyboards.

  The software supports multiple layers, tap-hold actions, macros, Unicode output and other advanced key behaviours. Configuration is handled through human-readable files, with live reloading available to make testing changes easier.

  This is free and open source software.

• Equicord – Discord client mod with over 300 plugins

  It retains Vencord’s familiar settings interface, theme support and custom CSS facilities, making migration straightforward for existing users. Equicord can modify Discord’s desktop application or be compiled as a browser extension for the web client. The accompanying Equilotl installer offers graphical and command-line installation workflows across Linux, Windows and macOS. Development combines frequent upstream merges with Equicord-specific fixes and additions. Using Equicord, like any unofficial Discord client modification, contravenes Discord’s Terms of Service and may expose an account to enforcement action.

  This is free and open source software.

• Gaffer – node-based VFX look development and production application

  Gaffer is a node-based VFX application for building, modifying, lighting and rendering complex scenes.

  It addresses look development and production automation rather than conventional hand-painted texture creation: artists and technical directors construct graphs that describe scene assembly, shaders, lights, render settings and image processing. A multithreaded deferred-evaluation engine calculates only the data needed for the current view or output, which helps the same graph scale from interactive work to final delivery. Gaffer also serves as an application framework, allowing studios to create custom nodes, interfaces and pipeline tools with C++ and Python.

  This is free and open source software.

• Apache Directory Studio – Eclipse-based LDAP browser and directory client

  Its LDAP Browser provides a graphical environment for navigating directory trees, running searches, and creating, editing, renaming, moving, or deleting directory entries. Connections, searches, and bookmarks can be retained, which is useful when administering several directory servers or repeatedly working with specific parts of a directory tree.

  The application brings several specialist tools together in one desktop interface. The LDIF Editor handles LDIF content and change records with syntax highlighting and content assistance, while the Schema Editor provides tools for editing attribute types, object classes, and OpenLDAP-format schemas. ApacheDS users also get configuration tooling, an integrated server environment, and an ACI Editor for creating access control information graphically or as source.

  Apache Directory Studio is built as an Eclipse RCP application from Eclipse/OSGi plugins. It can run as a standalone desktop application or its components can be installed into Eclipse. The project provides builds for Linux, macOS, and Windows.

  This is free and open source software.

• WebCord – privacy-focused Discord web client

  It does not reimplement or directly interact with the Discord API, allowing it to retain the service’s familiar interface and most web features. WebCord concentrates on privacy, permission management and Linux integration while providing workarounds for Electron, Chromium and Discord compatibility problems. It can block selected telemetry endpoints, disguise detectable web API modifications and restrict the resources Discord may load. Linux packages are available for several processor architectures. A major rewrite is underway, but the existing version continues to receive maintenance updates, dependency upgrades and targeted improvements such as better Wayland screen sharing.

  This is free and open source software.

• Ansizalizer – terminal UI to convert images to ANSI art

  Ansizalizer supports static images and animated GIFs. It also offers batch conversion, palette generation, dithering, image adjustments, transparency handling, settings presets and export to an ANSI text file or the clipboard.

  This is free and open source software.

• 7 Best Free and Open Source Geophysics, Seismology and Earthquake Engineering Tools

  Computational tools play an important role across these disciplines. They can process, analyse and visualise seismological observations, interpret seismic datasets, model subsurface structures, and solve forward and inverse geophysical problems. Such software helps researchers infer properties of the Earth from measurements collected at the surface or in boreholes.

  Other tools concentrate on seismic hazard and risk, estimating the likelihood and potential consequences of earthquakes. Earthquake engineering extends this work to the response of buildings, bridges and other structures, using numerical simulation to examine how engineered systems behave under seismic loading.

  Modern geophysical software also supports parameter estimation, optimisation and increasingly machine learning techniques. These approaches can assist with tasks such as seismic event detection, phase picking and the analysis of very large datasets.

  Here we feature the best free and open source tools for geophysics, seismology and earthquake engineering.

• BORG Calendar - desktop calendar and task tracking application

  BORG Calendar is a desktop calendar and task tracking application that combines personal scheduling, to-do management and project tracking in a single program.

  It is designed for users who prefer to keep their calendar data locally rather than depend on an online service, while still offering reminders, recurring appointments, private entries and broader task-management features.

  This is free and open source software.

• Material Maker – procedural texture authoring and 3D painting tool

  Material Maker is a graphical application for designing procedural materials and painting texture sets onto 3D models.

  Built on Godot, it represents generators, filters, transforms and outputs as interconnected nodes, so a material remains editable rather than being flattened into a fixed bitmap. Its workflow covers 2D and 3D textures, physically based rendering maps and graph-driven brushes in one interface. Results can be examined in 2D or on a configurable 3D preview before export. Graphs can be divided into reusable subgraphs and assets can be shared through the project’s online library, making the program useful for individual models and repeatable game-art pipelines.

  This is free and open source software.

• Commit – editor for Git and Mercurial commit messages

  Commit is a focused graphical editor for composing Git and Mercurial commit messages. It replaces a general-purpose text editor with a purpose-built interface that encourages clear, consistently formatted messages without attempting to become a complete repository client.

  Once configured, Commit opens whenever a supported version-control operation needs text. Messages can be accepted with Ctrl+Return or abandoned with Escape, fitting neatly into keyboard-driven workflows. The window identifies the project and current branch at a glance. Its GTK 4 and libadwaita interface fits naturally into GNOME desktops.

  This is free and open source software.