Thanks to Red Hat®, a 3 major new sets of fonts under GPL+exception license.
Named “Liberation” serif, sans and mono, those types are designed to subset the hegemony of proprietary helvetica, times and monospace courier new because metric compatible. It means distance between letters are the same, lenght of documents won’t change if helvetica is substituted by liberation sans font.

“Using these fonts does not subject your documents to the GPL–it liberates them from any proprietary claim”

Well cutted and with a very nice overall ambiance, the sans cut is particularly interesting, and much much nicer than another substitute for helvetica: the Arial. It is clearly affiliated to the Akzident Grotesk, but looks more neutral in the use. The serif cut is very far from the Times, and got formal similarities with the Vera Serif. But it gives a good contemporary, simple and elegant aspect to long readable texts, as far we tested it.

The wikipedia article

rpm font files and true type font files:
https://www.redhat.com/promo/fonts/