- Crystal Icon set by Everaldo Coelho.
- Nuvola by David Vignoni, originally created for KDE.
- Oxygen Project by KDE team.
- Tango Desktop Project - CC By SA
- Lazarus Project Icons - The Lazarus IDE Project (Delphi fork) has gratefully provided a collection of general purpose icons under CC-Zero license, credits Roland Hahn.
- Google Fonts - Material symbols and icons.
- Fontawesome - Designed for the web, may not work that well for desktop apps.
- famfamfam-silk
- Planet GNOME
- Planet KDE
- Planet Linux Kernel
- Qt blog
- Red Hat Developer Blog
- Planet Mozilla
- Fedora Magazine
- Planet Arch Linux
- Lxer
- OMG Ubuntu
- Phoronix - To keep up with the hardware stuff
- Producing Open Source Software - Karl Fogel's free book covering all aspects of open source project management.
- Free as in Freedom by Richard Stallman
- The Architecture of Open Source Applications
- Getting started with Open source development (PDF)
- Open Source for Business - A Practical Guide to Open Source Software Licensing
- Philosophy of the GNU Project
- Why Open Source misses the point of Free Software
- GNU Software
- Free Learning Resources - GNU
- Letter from RMS to Tim O'Reilly
- The Bug Nobody is Allowed to Understand
- How I do my computing - Richard Stallman
- Saint IGNUcius - Richard Stallman