The great news is that the number of choices for open source icons has continued to grow. There are a variety of icons sets for designers and developers to incorporate into their projects and applications.
- Open Icon Library has over 5,000 icons that are available under open licenses.
- Raphaël has a set of 104 icons licensed under the MIT license.
- Jamie at 37signals has released an icon set under CC Univeral 1.0 and the WTFPL.
- Crystal icon set is released under the LGPL
- Nuvola free icon set is released under the LGPL 2.1.
- Tango icon set continues to be a great set
- Oxygen icon theme released under CC Share-A-Like 3.0 or LGPL
- Boolean mini-icon set (16 x 16 pixel) released under CC Attribution 3.0
- Project Icons are a set of 165 32px icons released under CC Attribution 3.0
- PictICO is a set of 100 scalable vector icons released under Creative Commons Attribution-Noncommercial 3.0 Unported.
- Webappers has a great list of open source and free icon sets available.
- Kirk Montgomery has a list from 2008 of free and open source icons.
- Androidicons is a set of 30 PNG CC Attribution-Share-A-Like icons for Android developers
- Glyphish is a set of 130 AI & PNG vector icons for iPhone & iPad developers under CC Attribution license
- Mark Arteaga’s Metro Icons for Windows Phone 7
Steven Garrity has launched the Tango Project which is a set of icon style and naming guidelines for the Linux desktop. The project includes a great base set of icons licensed under the CC Share Alike
Brent Simmons post from May 2002 attrached a number of great comments for sources for open-source icons.
- Ximian Developer Art
- Xicons though no guarrantee that the icons are open-source
- famfamfam 16 pixel by 16 pixel icons released under the Creative Commons Attribution License
I’ve also posted about non-open-source but very inexpensive and professional icons.