This is a guest post by Raoul's brother Etienne, who is not only passionate about fonts and typefaces, but also open source software.
Any modern operating system includes a wide selection of typefaces so that one can get working immediately. Windows comes with its ClearType fonts installed by default, including the award-winning Calibri, while Apple’s OS X has included the coveted Helvetica ever since it was NeXTSTEP back in 1988.
But what about those of us who choose free and open-source software? How can we ensure that the typefaces we use are free from proprietary restrictions? How can we share our fonts with our friends freely and legally? And, most of all, how can we make those using proprietary software jealous of our beautiful documents and publications?
I have thus put together a list of my top 10 free or open-source typefaces. While there are indeed a large number of fonts available free of charge, I have ensured that those listed here conform to either the Free Software Definition or the Open Source Definition.
10. URW++ Ghostscript Collection
Ghostscript provides a free software interpreter for PostScript, and includes free alternatives for PostScript fonts such as Helvetica and Courier. While the basic Ghostscript fonts are already included in most Linux distributions, there are free alternatives to even more famous proprietary fonts available.
The Oxygen font family is a fantastic new family created specifically for KDE. It is not only legible at small sizes, but also has great curves that one can see in large print. Unfortunately, it is not high up on my list due to its incomplete status.
The titular typeface of the Linux distribution, Ubuntu is very good-looking and fresh. It works well at all sizes, it is available on Google Documents, and has too many variants to count. The only reason why it is low down on this list is due to its overuse on web pages.
Gill Sans is a staple typeface for graphic designers, and while Cabin is not at all a drop-in replacement, it is still inspired by Gill. It has a very clean attractive feel, while there are also condensed and sketch versions available.
6. Josefin Sans & Slab
5. Open Sans
A great typeface for documents, Open Sans is based on Droid Sans and created by the same person. It extends the original Droid into a large family covering most languages. It is available in many weights and also as a condensed version.
Asap is a very attractive typeface with rounded corners which is very easy on the eyes. It is very versatile, perfect for professional needs as well as children’s books and even large posters.
If you are looking for something more suited for large posters or slides, then Rawengulk is an exquisite font. It has some of the most beautiful curves one will ever see and a sans-serif variant. Unfortunately, it has no italic variants and is also not suitable for large paragraphs of text.
2. Source Sans Pro
Source Sans is a free and open-source font family by Adobe, which may surprise some. It is very attractive, yet still sedate enough for everyday document use. I recommend this above Arial, Helvetica/Nimbus Sans, and perhaps even Open Sans.
1. Linux Libertine Family
My number-one favourite font is Linux Libertine, but not due to its name. This is a font originally created to replace Times, yet it has far surpassed its original intention. If fully supports most language character sets, and it is incredibly beautiful and exquisite, especially at large sizes where one can see its fantastic curves. I recommend this typeface for documents, publications, and especially books and theses. It is ready to be used in TeX/LaTeX, and can be found in OpenType, TrueType and Graphite formats amongst others. It comes with the accompanying Linux Biolinum, and the two work so well together one can almost forget about any others.
Since this is a top-10 list, I have not included other excellent typefaces such as the Liberation, PT, and DejaVu families, which many people use daily. Take a wander through Google Webfonts and FontSquirrel for many other fonts, although some may have non-free licenses.