Material Design Icons
Google have open-sourced a collection of interface icons which are part of their products and services:
Today, Google Design are open-sourcing 750 glyphs as part of the Material Design system icons pack. The system icons contain icons commonly used across different apps, such as icons used for media playback, communication, content editing, connectivity, and so on. They’re equally useful when building for the web, Android or iOS.
Should be useful for designers and developers (and probably abused by net artists).