iPhone Mockups by Previewed - Beautiful iPhone mockups to present your app
Facebook Design - Devices - Images and Sketch files of popular devices.
Previewed - Beautiful mockups & graphics for your next app
Design Cell - Beautiful multipurpose mockups for iOS
Adobe Spark Post - Adobe Spark Post is the fun and fast way to create stunning graphics for all occasions.
Clay Mockups - Free set of beautiful device mockups for your designs