Base UI Sketch Framework - Huge set of everything you need to design and prototype
Carrd - Simple, responsive one-page site creator.
SketchCasts - A weekly screencast, all about how to use Sketch
Startup Framework - Create a beautiful, responsive website in under an 1 hour
UiSketcher - Easily sketch user interface with your pen-enabled device!
Front-End Checklist - The perfect Front-End Checklist for modern websites 🗂