Mediamodifier - Create beautiful designs and product mockups in seconds.
Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
mockDrop - Is a webapp for creating free device mockups including your screenshots.
MockupBro - Create awesome mockups without any graphic software. Just choose mockup, upload your design and download your image.
StoreShots - StoreShots helps you create iOS & Android App Store Screenshots with Device Frame and Caption...
Placeit - Generate realistic product shots in seconds