This set of 113 free 10x10px grayscale mini icons from Brand Spanking New is a nice set of small, unobtrusive icons that can function inline with text or in places where smaller type might be used, e.g. with metadata. This is not a new set of icons, but I'd like to start collecting examples of icons here.

http://www.brandspankingnew.net/archive/2006/12/hohoho.html