Google Design Sprint Kit - Your resource for planning and running a Design Sprint
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
FlowMapp - FlowMapp is a UX planning tool for creating visual sitemaps and user flow.
Facebook Design - Resources for Designers from the Facebook Design team
Craftwork - A collection of User Interface resources made by Craftwork
InVision Studio - The world’s most powerful screen design tool