GLYPHICONS
GLYPHICONS is a library of precisely prepared monochromatic icons and symbols, created with an emphasis on simplicity and easy orientation. The GLYPHICONS Free version is released under Creative Commons Attribution 3.0 Unported (CC BY 3.0).
We'll need to figure out an appropriate way to provide attribution in Confluence if we decide to use these broadly. In the meantime, I am experimenting with a couple of the icons for a quick fix to a request.