Freebbble!

License: “It is absolutely free of charge I provide anyone with a right to use this UI Kit (and its further updates) for personal or commercial purposes without indicating the name of the author!”

Lookamore UI Kit for Android is a free UI Kit design resource made by Dribbble user Artem Tolstykh. As far as I can tell, its license is Free for Commercial and Personal Purposes.

Helpful hint: Dribbble users are nice. If the license is unknown, it is usually because they forgot to mention it explicitly; not because they were being stingy. Ask nicely and they will probably allow you to use it.