Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
shotsnapp - Create beautiful device mockup presentation
Mockup Generator - Create attractive product screenshots with just a few clicks
Device Shots - Generate high-resolution device mockups using a screenshot.
Gfxtra - Gfxtra is a free web-based platform that is created for designers who want to get new ideas and designs.
Simple Mockups - Minimalistic devices mockup pack for Sketch & Photoshop