Open Doodles

Open Doodles is a set of free illustrations that embraces the idea of Open Design. You can copy, edit, remix, share, or redraw these images for any purpose without restriction under copyright or database law (CC0 license.)

I hope that this kind of resource makes it easier for designers to show the value of illustration in their mockups. Maybe you use these images as placeholders, before you're ready to hire an illustrator. Or perhaps this will encourage others to create their own kit and share it with the world.