Sites like stellarforces.com

Damien Guard's personal blog on software development, typography and vintage computing, with EF Core and VTX5000 articles

Warzone 2100, a free open-source 3D real-time strategy video game with downloads for Windows, macOS and Linux

Invent with Python is a programming learning site with free books, tutorials and a blog by Al Sweigart

Green Tea Press, publisher of free programming, data science and modeling textbooks by Allen B. Downey

Matchmaking lobby, chat room and leaderboards for online multiplayer games of Marathon and Aleph One, run by its community

The FreeBSD Project's official site on the open-source Unix-like operating system, its downloads, documentation and community

The official home of Xfce, a lightweight desktop environment for UNIX-like operating systems, with release news and blog posts

OpenShot, a free open-source video editing software for Linux, Mac and Windows, with a project homepage and multilingual pages

The LaTeX Project's website on LaTeX, the document preparation and typesetting system for technical and scientific publishing, with downloads, bug reporting, help and licence text

Stellarium, a free open-source planetarium software program for rendering realistic night sky views, with developer documentation

The Battle for Wesnoth is an open source, turn-based fantasy strategy video game, with its project's developer documentation and release notes

Personal home page of Eric S. Raymond hosting his open-source software, FAQs, essays and the Retrocomputing Museum

Calibre, a free open-source e-book management software for converting, organising and syncing e-books across devices

GCompris is a free educational software suite for children, with activities for learning on computers

Puppygames, an independent video game studio's site with news, blog, press assets and games such as Paladin and Ultratron

Urban Terror, a free multiplayer first-person shooter game and community site with developer news and tournament announcements

Leanpub, a self-publishing platform where authors sell early-access and in-progress books, including technical titles on software and AI

Bay 12 Games, the independent developer's site for Dwarf Fortress and other games, including Liberal Crime Squad and WWI Medic, by Tarn Adams

Indie Retro News, a blog covering new indie games and homebrew ports for retro platforms such as the Amiga and PC

Bugzilla project's website on the open-source bug-tracking software for planning and releasing software, with documentation, history and donation pages

A BitTorrent client called Deluge, with GTK, web and console interfaces, for Linux, macOS, Unix and Windows

django CMS is an open source content management framework built on Django, for enterprise websites and agencies

Free Download Manager, a free download accelerator and organizer for Windows, macOS, Android and Linux, with torrent support

The MacPorts Project's official site offering a package manager for installing open-source software on macOS and other Unix-like systems

TWiT, an internet television network of tech podcasts and live shows founded in 2005 by Leo Laporte

The Open Source Geospatial Foundation website, a nonprofit hub supporting geospatial open source software projects, their community, events and governance

The NetBSD Project's home site for its free, portable Unix-like operating system, with documentation, platform lists, news and downloads

Org Mode for GNU Emacs: a plain-text major mode and project site for notes, to-do lists, planning and literate programming

An international community developing free and open-source software, including the Plasma desktop and KDE applications

Damn Interesting, an English-language blog of obscure true stories on science and history by Alan Bellows, running since 2005

SciPy, an open source Python library of algorithms for scientific computing, covering optimization, integration, interpolation, statistics and differential equations

The GNOME project's website, presenting its free and independent desktop computing platform and its community, in English and several other languages

The official home of the Haskell programming language, covering its compiler GHC, build tool Cabal, installer GHCup and community resources