Sketch Measure - Spec tool for developers and teammates
Smartmockups - Create stunning product mockups, easily and online.
Zeplin - Collaboration app for UI designers & frontend developers
AppLaunchpad - Create free beautiful screenshots for App store/Google play
Marketch - Marketch is a Sketch 3 plug-in for automatically generating html page that can measure and get CSS...
Placeit - Generate realistic product shots in seconds