Below is a list of Google fonts which will work for longer texts and most come in, at least, these four styles - Normal, Normal Italic, Bold and Bold Italic.
The font size for all the examples is 18px.
To use one of these fonts, place this in the <head> of your page:
<link href='http://fonts.googleapis.com/css?family=Foo:400,700' rel='stylesheet' type='text/css'>
with the mark up below the font name in place of: family=Foo:400,700'
And in your style sheet add the fonts name: font-family:'Foo'
The number one, the lower case l and the captial I (1lI) are added at the end of each font to provide a quick test of legibility. The fi and ffl are after those to show if ligatures can be enabled in the font.
Alegreya Alegreya Alegreya Alegreya 1lI fi ffl
family=Alegreya:400italic,700italic,400,
700'
Alegreya SC Alegreya SC Alegreya SC Alegreya SC 1lI fi ffl
family=Alegreya+SC:400,400italic,700,
700italic'
Almendra Almendra Almendra Almendra 1lI fi ffl
family=Almendra:400,400italic,700,
700italic'
Amaranth Amaranth Amaranth Amaranth 1lI fi ffl
family=Amaranth:400,400italic,700,
700italic'
Archivo Narrow Archivo Narrow Archivo Narrow Archivo Narrow 1lI fi ffl
family=Archivo+Narrow:400,400italic,700,
700italic'
Averia Serif Libre Averia Serif Libre Averia Serif Libre Averia Serif Libre 1lI fi ffl
family=Averia+Serif+Libre:400,700,300italic,400italic,700italic',
700italic'
Cabin Cabin Cabin Cabin 1lI fi ffl
family=Cabin:400,700,400italic'
Cantarell Cantarell Cantarell Cantarell 1lI fi ffl
family=Cantarell:400,700,400italic,
700italic'
Caudex Caudex Caudex Caudex 1lI fi ffl
family=Caudex:400,700,400italic,
700italic'
Cardo Cardo Cardo 1lI fi ffl
family=Cardo:400,400italic,700'
Chivo Chivo Chivo Chivo 1lI fi ffl
family=Chivo:400,400italic,900,
900italic'
Cousine Cousine Cousine Cousine 1lI fi ffl
family=Cousine:400,700,400italic,
700italic'
Crimson Text Crimson Text Crimson Text Crimson Text 1lI fi ffl
family=Crimson+Text:400,400italic,
700,700italic'
Droid Serif Droid Serif Droid Serif Droid Serif 1lI fi ffl
family=Droid+Serif:400,700,400italic,
700italic'
Droid Sans Droid Sans Droid Sans Droid Sans 1lI fi ffl
family=Droid+Sans:400,700'
Droid Sans Mono 1lI fi ffl
family=Droid+Sans+Mono'
Gentium Basic Gentium Basic Gentium Basic Gentium Basic 1lI fi ffl
family=Gentium+Basic:400,700,400italic,
700italic'
Gentium Book Basic Gentium Book Basic Gentium Book Basic Gentium Book Basic 1lI fi ffl
family=Gentium+Book+Basic:400,
400italic,700,700italic'
Exo Exo Exo Exo 1lI fi ffl
family=Exo:400,700,400italic,700italic'
Istok Istok Web Istok Web Istok Web 1lI fi ffl
family=Istok+Web:400,700,400italic,
700italic'
Josefin Sans Josefin Sans Josefin Sans Josefin Sans 1lI fi ffl
family=Josefin+Sans:400,700,400italic,
700italic'
Josefin Slab Josefin Slab Josefin Slab Josefin Slab 1lI fi ffl
family=Josefin+Slab:400,700,400italic,
700italic'
Lato Lato Lato Lato 1lI fi ffl
family=Lato:400,700,400italic,
700italic'
Libre Baskerville Libre Baskerville Libre Baskerville Libre Baskerville 1lI fi ffl
family=Libre+Baskerville:400,400italic,700,'
Lora Lora Lora Lora 1lI fi ffl
family=Lora:400,700,400italic,
700italic'
Merriweather Merriweather Merriweather Merriweather 1lI fi ffl
family=Merriweather:300,400,700,900, 300italic,400italic,700italic,900italic'
Merriweather Sans Merriweather Sans 1lI fi ffl
family=Merriweather Sans:300,400,700,800'
Neuton Neuton Neuton Neuton 1lI fi ffl
family=Neuton:300,400,700,400italic'
Nobile Nobile Nobile Nobile 1lI fi ffl
family=Nobile:400,400italic,700,
700italic'
Noto Serif Noto Serif Noto Serif Noto Serif 1lI fi ffl
family=Noto Serif:400,400italic,700,
700italic'
Noto Sans Noto Sans Noto Sans Noto Sans 1lI fi ffl
family=Noto Sans:400,400italic,700,
700italic'
Open Sans Open Sans Open Sans Open Sans 1lI fi ffl
family=Open+Sans:400italic,700italic,
400,700'
PT Sans PT Sans PT Sans PT Sans 1lI fi ffl
family=PT+Sans:400,700,400italic,
700italic'
PT Serif PT Serif PT Serif PT Serif 1lI fi ffl
family=PT+Serif:400,700,400italic,
700italic'
Philosopher Philosopher Philosopher Philosopher 1lI fi ffl
family=Philosopher:400,700,400italic,
700italic'
Playfair Display Playfair Display Playfair Display Playfair Display 1lI fi ffl
family=Playfair+Display:400,700,400italic,
700italic'
Puritan Puritan Puritan Puritan 1lI fi ffl
family=Puritan:400,700,400italic,
700italic'
Quantico Quantico Quantico Quantico 1lI fi ffl
family=Quantico:400,400italic,700,
700italic'
Quattrocento Sans Quattrocento Sans Quattrocento Sans Quattrocento Sans 1lI fi ffl
family=Quattrocento+Sans:400,400italic,700,
700italic'
Rambla Rambla Rambla Rambla 1lI fi fflfamily=Rambla:400,400italic,700,700italic'
Roboto Roboto Roboto Roboto1lI fi ffl
family=Roboto:400,400italic,700,700italic
Roboto Slab Roboto Slab 1lI fi ffl
family=Roboto:100,300,400,700
Roboto Condensed Roboto Condensed
Roboto Condensed Roboto Condensed 1lI fi ffl
family=Roboto+Condensed:400,400italic,700,700italic'
Rosario Rosario Rosario Rosario 1lI fi ffl
family=Rosario:400,400italic,700,
700italic'
Scada Scada Scada Scada 1lI fi ffl
family=Scada:400italic,700italic,400,
700'
Simonetta Simonetta Simonetta Simonetta 1lI fi ffl
family=Simonetta:400,900,400italic,
900italic'
Sorts Mill Goudy Sorts Mill Goudy 1lI fi ffl
family=Sorts+Mill+Goudy:400,400italic'
Tinos Tinos Tinos Tinos 1lI fi ffl
family=Tinos:400,400italic,700,700Italic'
Titillium WebTitillium Web Titillium Web Titillium Web 1lI fi ffl
family=Titillium+Web:400,400italic,700,
700italic'
Ubuntu Ubuntu Ubuntu Ubuntu 1lI fi ffl
family=Ubuntu:400,700,400italic,
700italic'
Ubuntu Mono Ubuntu Mono Ubuntu Mono Ubuntu Mono 1lI fi ffl
family=Ubuntu+Mono:400,700,400italic,
700italic'
Volkhov Volkhov Volkhov Volkhov 1lI fi ffl
family=Volkhov:400,400italic,700,
700italic'
Vollkorn Vollkorn Vollkorn Vollkorn 1lI fi ffl
family=Vollkorn:400italic,700italic,400,
700'
These and many other fonts may be found at Google Fonts.