Vector Junky is a repository of free vector artwork. Plenty of categories, over 9,000 images, don’t forget to donate if you can.
vectorjunky.com is an online gallery of free vector graphics. All the images on this site are free for personal use and a lot of them for commercial use, if you use any of the free vector art it would be nice if you could provide a link back to the authors web site. (But not always a requirement .)