Spectre.css - Lightweight, responsive and modern CSS framework for faster and extensible development.
Contra Wireframe Kit - Open source wireframe kit for design and prototyping 🚀
Wing-project.org - WING - Wireless Mesh Network for Next-Generation Internet
Platforma - Wireframe library of layouts and UI elements
Whimsical Wireframes - Lightning fast wireframing with real-time collaboration.
Craftwork - A collection of User Interface resources made by Craftwork