Responsive View
Test your responsive design across different devices
15 Alternatives To Responsive View
2015 Design Tools
Results from survey of 4,000+ designers on their fave tools.
Design Principles
An open source repository of design principles and methods
Landscape by Sprout Social
An interactive tool for social media image resizing
Placid
Generate og:images and twitter:images automatically
Rapid Responsive Design
Kill your artboards, design for all sizes faster
Salieo
Intelligently responsive images.
Squash 2 for Mac
The easiest way to compress and optimize images for the web