Free humanist sans-serif font, similar to Adobe Myriad. Available in light,
regular & bold versions. Designed by Sora Sagano.

Workhorse serif font that is designed to be a metrics-compatible drop-in
replacement for Cambria.
Contains Regular, Bold, Italic, and Bold Italic version.

Designed by Huerta Típografica for Google.

Modern, friendly sans-serif font derived from the Lato font that is
designed to be a metrics-compatible drop-in replacement for Calibri.
Contains Regular, Bold, Italic, and Bold Italic version.

Designed by Lukasz Dziedzic of tyPoland for Google.

Modern, friendly slab-serif font optimised for high-resolution screens, such as
those of e-book devices. Contains Regular, Bold, and Italic version.

Designed by Sol Matos of Huerta Tipográfica.

Friendly free sans-serif font designed for Firefox OS. Fira Sans
(née Feura Sans) looks very similar to FF Meta, but has a larger x-height to
improve appearance on screens. Contains light, regular, medium & bold weights
of Fira Sans. Contains bold & regular versions of Fira Mono.

Designers: Ralph du Carrois & Erik Spiekermann.