Device Shots - Generate high-resolution device mockups using a screenshot.
Ruby Weekly - A free, once–weekly e-mail round-up of Ruby news and articles.
Facebook Design - Devices - Images and Sketch files of popular devices.
Laravel - A PHP Framework For Web Artisans
Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
Codewars - Achieve code mastery through challenge.