Sites like zimjs.com

Box2D is a 2D physics engine for games, with a blog by its creator Erin Catto on game physics and programming

Emmet, a plugin toolkit for writing HTML and CSS faster in text editors, by developer Sergey Chikuyonok

Qiita, a Japanese knowledge-sharing platform where engineers publish technical articles and tutorials on programming and software development

Can I use..., a reference site of browser support tables for web features such as HTML5, CSS3 and JavaScript

GIMP, the free open-source cross-platform image editor project, with its official website, bug reports, documentation and news

A learning website teaching children textual programming through the Hedy language, with step-by-step exercises for classrooms

An online database of scanned illustrations from old books, mostly 19th and 20th century, published by Old Book Illustrations

Cacti, an open-source RRDTool-based network monitoring and graphing tool with a data collector called Spine

TecMint, a Linux how-to blog with tutorials and guides by Ravi, founded in 2012

Path of Exile, a free online action RPG set in the dark fantasy world of Wraeclast, with news, forums and trade

The Zig programming language project's website, covering the general-purpose language, toolchain, documentation, and the Zig Software Foundation

Selenium, an open-source browser automation tool for web application testing, documented on its official project website

Free online activities for couples, including two-device quizzes, couple games, conversation questions and relationship tools, from SyncWithLove

A online museum cataloguing screenshots and videos of old websites, apps, software and Flash games from the 1990s to late 2000s

OSNews, a long-running news and discussion site covering operating systems, computing, software development and technology news

Parcel, a zero-configuration JavaScript build tool for the web, with release announcements and blog posts from its team

Yarn, a JavaScript package manager; its documentation and API reference for the @yarnpkg packages

ccMixter is a community website for sharing and remixing music licensed under Creative Commons licenses

The Rollup JavaScript module bundler's official website, with documentation, FAQs, an online REPL and browser build guides

Fyne.io is an open-source Go toolkit for building cross-platform desktop and mobile apps, with events, vision and sponsorship pages

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

Giant in the Playground Games is a webcomic publisher and shop for Rich Burlew's Order of the Stick comic and merchandise

Mocha, a JavaScript test framework for Node.js and browsers, with its project documentation and API reference

Free game assets, tools and games by Kenney, a studio producing 2D and 3D art for game developers

WinSCP, a free open-source SFTP and FTP client application for Windows file transfers between local and remote computers

Bellingcat, an independent online investigations collective publishing open-source research, verification guides, and reports on power and accountability

The Rabbit Room, a Christian community site publishing articles, music, poetry, and classical playlists alongside books and events, with contributors such as Mark Meynell and Ashlyn McKayla Ohm

Silex, a free open-source visual no-code website builder for static sites, part of the OW2 community

PixiJS is an open-source HTML5 rendering library for interactive 2D graphics, games and cross-platform applications, maintained by a volunteer core team

GDevelop, an open-source no-code game engine for making 2D and 3D games and publishing them on Steam and app stores

DEV Community, a English-language online community and blogging platform where developers publish posts, tags and challenges about programming and software

Studio JAW, the game, VRChat and Unity development studio of Josephine Anna Wall, with workshop streams, an AI companion and music

A security-focused, compartmentalizing desktop operating system based on Xen, with project news, hardware compatibility list and documentation

RolandRadio.net is an online radio station streaming Amstrad CPC chiptune music around the clock, founded in 2015 by Kangaroo MusiQue

OpenRefine is a free, open source desktop tool for cleaning, transforming and extending messy data