Alegreya Sans is an open-source typeface designed by Argentinian designer Juan Pablo del Peral. It was created as the sans-serif companion to Alegreya, so it shares a similar calligraphy-inspired, humanist design. Alegreya Sans is available in seven weights with matching italics and is one of the best free fonts available on Google Fonts, in my humble opinion. Sadly it seems to be underused compared to other popular humanist Google Fonts such as Open Sans, but I’m hoping we’ll start to see it used more on the web in the future.
Font research done for you.