Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
Device Shots - Generate high-resolution device mockups using a screenshot.
Placeit - Generate realistic product shots in seconds
Facebook Design - Devices - Images and Sketch files of popular devices.
Mediamodifier - Create beautiful designs and product mockups in seconds.
mockDrop - Is a webapp for creating free device mockups including your screenshots.