I found this not too long ago and it's been an excellent resource for me! Whether I'm actually designing my own heraldry for a character, organization, kingdom, etc, or simply need to steal one of the anonymous ones really quickly for something to show my players because they asked!

http://www.fantasyshields.com/

EDIT - Clicking "The Herald" link at the top takes you to the design page. Clicking "The Lists" takes you to a list of all the recently designed heraldry, some of them named by their creators, many of them anonymous.