Smartmockups - Create stunning product mockups, easily and online.
Radix Icons - A crisp set of 15×15 icons. Open source.
AppLaunchpad - Create free beautiful screenshots for App store/Google play
MakeAppIcon - MakeAppIcon resizes and optimizes your icon designs into all formats needed for iOS and Android mobile app!
Placeit - Generate realistic product shots in seconds
Bjango App Icon Templates - App icon templates for PS, Ai, Sketch and Affinity Designer