We at Mixamo just compiled a list of the top 10 free resources for indie devs. Many of our users are making game/apps for little or no cost up front at all. We thought it would be helpful to perhaps share some of these freebies for those who might not know of them all.
You can check it out here: Mixamo Top 10 Free Resources
Also if you can think of any other awesome free tools please let us know and share! This is not intended as a comprehensive list but just some good finds we wanted to mention.