For clipart that is free to use, even for unlimited commercial use, look no further than the Open Clip Art Library. The site is an incredible resource. Any clipart can be located instantly with the !oca bang.
Syntax: !oca keyword(s)
Example: !oca duckling
RSSPBRRY is a free and open source RSS feed reader and Internet tastemaker (more information forthcoming). The software is available for download on Github.