Design Principles - An open source repository of design principles and methods
Off Of - A Simple Percentage Calculator for iOS
Facebook Design Resources - A collection of free resources made by designers at Facebook
Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.
Facebook - Connect with friends, family and other people you know. Share photos and videos, send messages and get updates.
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.