I'm very happy to have <a href="http://www.windowsphone.com/en-US/apps/8a5a0a71-6d97-4284-863a-c14424e23ecc">Icons</a> in the Marketplace. Please help by rating the application and showing the icons to your fellow Windows Phone developers.
!<a href="/files/icons_marketplace.png">screenshot</a>
So, in the future I'm going to be loading in the XAML vector icons and allowing users to select a color, opacity, and size. Might even allow one to batch export all the icons and attach as a zip to an email.