Designmodo.com ( http://designmodo.com/linecons-free ) 
camera, cloud, diamond, fire, gear, heart, key, like, record, science, star, world

Piotr Makarewicz ( https://dribbble.com/ilepixeli )
house, person

icojam ( http://www.icojam.com/blog/?p=668 )
apple, carrot, fish, flower, steak, tree