Invision - Prototyping and collaboration for design teams
Anima App - Design, get feedback, convert to code, publish, iterate.
Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
Sketch Repo - Collection of resources for anyone who uses Sketch
Craftwork - A collection of User Interface resources made by Craftwork
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.