Ready to use SVG icons for the web.
#icons
Emoji cheat sheet
Nice cheat-sheet for the text version of emoji on platforms which support them.
Iconic
The first and only icon system created for the modern web plus all the tools to make them your own.
Flat Icons & Icon Fonts
Huge collection of flat icon fonts for use in web development.
IcoMoon App
Pretty amazing online app that allows you to build your own custom webfont, containing all sorts of awesome vector/font icons for social media etc. Brilliant.
Social Media Icons
Set of very nicely-designed and relatively consistent social media icons. Perfect for lifestreams/activity streams.
15 wonderful set of icons for web design
15 wonderful set of icons for web design
Icon collections that are perfect for the web. Not all of them a free.