Taken from: https://dribbble.com/msenyil/projects/153116-Flag-Set

Free Flat Flags
AUGUST 12, 2013
Hey guys, I made 100 flat flags to use in my project. Thought I'd share it with you guys, maybe some of you can use it in your own projects. Thanks to @Creativedash for the animation inspiration Download PSD

Nate Cavanaugh
These are really awesome :) Do you have a license for reusing them?

Muharrem Senyil
@Nate Cavanaugh No man, it's totaly free. But don't try to sell it :P