User interface and interactivity of website are vital aspects of any web design that affect it much. Using icons along with navigation links is one key element to make website effective. Yet, creating icons sets is very time consuming process. Hence designers like you should use icons that already have been created for you. Here are some of the best icon sets for use in any web application designs.Icon Sets for Designing Web Apps
Tango Icon Library
Crystal Clear
Coquette Icons
Aesthetica Icons
Diagona Icons by Pinvoke
Fugue Icons by Pinvoke
FAMFAMFAM – Silk
Jonas Rask Design Icons for Developers
ASP.NET Icons
Web Application Icons Set
Free web development icons #4 SE
Knob Buttons Toolbar Icons
Simplistica Icons
Function Icon Set
Milky
Simplicio
Fresh
FAMFAMFAM – Mini
Developpers Icons
Monofactor Vector Icons
IVista Icon Pack 2