Materia icon set is using Material style guide for icons in 24x24 grid. These icons are a perfect choice to use in Android.
Materia contains 3120 vector icons divided into following categories: appliances, arrows & symbols, auto technic, baby, basic, biology, buildings, communication, computers, database, design, finance, food, fruits & vegetables, hardware, holiday, human, interface, interior, kitchen, lightning, maps & travel, military, multimedia, music, nature, office, phone, presentations, science, security, social_free, space, sport, tools, transport, video & games, weather.
AI (Adobe Illustrator file CS5 version). 24x24 px icons. Each icon category is on it's own layer.
PSD (Adobe Photoshop file). Size: 24x24 px.
CSH (Adobe Photoshop custom shapes).
EPS (Adobe Illustrator v10) layered file with all categories and EPS files for each category.
SVG files for individual icons.
Transparent PNG. Sizes:
LDPI 18x18 px.
MDPI 24x24 px.
HDPI 36x36 px.
XHDPI 48x48 px.
XXHDPI 72x72 px.
XXXHDPI 96x96 px.