Select an icon collection. Once loaded, just click on the icons you want, your custom flairs set will get filled. When ready, just click on the "Copy flairs set" button, and import 
button on gadget's toobar.
You can suggest a new icon collection and have it displayed here ! Just join the group and post your favorite icon collection. Remember, they must be free use (personal and commercial), should be available in PNG or GIF format, and sized as 16x16.