Smartmockups - Create stunning product mockups, easily and online.
Invision - Prototyping and collaboration for design teams
Josh Parnham - Software Developer and organiser
Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
Gmail Screenshot by cloudHQ - Simplifying sending screenshots from gmail (free)
Craftwork - A collection of User Interface resources made by Craftwork