Design Principles - An open source repository of design principles and methods
Accessify - Manage access to all the services your team uses
Facebook Design Resources - A collection of free resources made by designers at Facebook
Stark for FigJam - Stark for FigJam provides designers, engineers, and product managers role specific accessibility checklists.
Facebook - Connect with friends, family and other people you know. Share photos and videos, send messages and get updates.
Nibbler - Free tool for testing how good your website is, and what you can do to improve it. Check accessibility, SEO, social media, compliance and more.