Ionicons Icon Font

Ionicons is an icon font which is used on several StudioPress themes, which enqueue the font directly, but you're free to add the font via custom CSS. The icon font is free, open source, and includes hundreds of icons in a flat design. Icons are called using the HTML5 i element, which now has the specific semantic purpose of "representing text 'offset from its surrounding content without conveying any extra emphasis or importance, and for which the conventional typographic presentation is italic text.'" A class added to the i element specifies the icon to be displayed. The font currently adds about 114 Kb to a site's page weight, but that's sure to change as icons are added or removed.