AppLaunchpad - Create free beautiful screenshots for App store/Google play
Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
Placeit - Generate realistic product shots in seconds
Smartmockups - Create stunning product mockups, easily and online.
iOS Jetpack - Beautiful easy-to-use screenshot templates for App Store
MockMagic - A free, easy-to-use device mockup generator