P.J. Onori also knows as SRD (his blog) has provided on his playground a nice list of icon sets free for use under Creative Commons License. For those who don’t know, P.J. Onori is a product designer living in San Francisco and working (currently at least) at SeaBright. He’s a big fan of dialog and constructive confrontation and enjoys being shown how he is wrong (which happens frequently).
Ok, now that we know SRD, lets start with the icons.
CUE icon set
Cue is a public domain gestural icon set which focuses on legibility and symbolic representation. The icon pack comes in PNG (4 sizes), InDesign, SVG and Omnigraffle formats. Also, CUE icon pack comes with or without labels.
Iconic icon set
Iconic icon pack is a minimal set of icons containing 177 marks in raster, vector and font format. To give the greatest flexibility, the pack comes with icons in PNG, SVG, SWC, OFT/TTF/EOT and Omnigraffle stencil formats. Besides this, the pack comes in 14 colors and 5 sizes (8×8, 12×12, 16×16, 24×24, 32×32 pixels). The great thing is that if the colors/sizes don’t fit your needs, you can always make your own with the SVG.
Bitcons icon set
Bitcons icon pack features 120 icons (pixel icons) that comes in 3 different formats (16×16, 32×32, 64×64 pixels … the 32×32 and 64×64 icons have a chunkier look, maintaining the pixel style) and and 10 variety of colors that hit all major HUEs. The icons are extremely small, with actual marks varying between 8×8 to 12×12 pixels. Due to the fact they are pixel icons, the marks stay legible even at the small sizes allowing for low profile aesthetics. There is also a CSS friendly version of Bitcons that can be found here