Hopefully you are familiar with The Noun Project. The mission of this project:The Noun Project collects, organizes and adds to the highly recognizable symbols that form the world's visual language, so we may share them in a fun and meaningful way. Currently there are about 1000 icons in the collection.
The images are high-quality vector based SVG files. But they are black only, would it not be nice to be able to personalize them like these: