Be careful, though- these are the most overused set of icons. They're like the Comic Sans or Papyrus of icons. Like another commenter said, if you're looking for some less-used icons, try these two (free) sets:
I think that's pretty misleading comparing Silk to Comic Sans. A more suitable comparison would be to something like Helvetica or Times New Roman. Ubiquitous and overused but still a dependable choice.
Be careful, though- these are the most overused set of icons. They're like the Comic Sans or Papyrus of icons. Like another commenter said, if you're looking for some less-used icons, try these two (free) sets:
http://p.yusukekamiyamane.com/