Clay Mockups - Free set of beautiful device mockups for your designs
Craftwork - A collection of User Interface resources made by Craftwork
Icons8 - Free app for Mac & Windows already containing 39,800 icons. Allows to search and import icons…
AppLaunchpad - Create free beautiful screenshots for App store/Google play
Previewed - Beautiful mockups & graphics for your next app
Ape Mockups - A huge hand-curated collection of free high-quality mockups