Bootstrap - Simple and flexible HTML, CSS, and JS for popular UI components and interactions
Get-It - Get Free HTML5 and Tumblr Website Templates.
Element UI - A Desktop UI Library. Element, a Vue 2.0 based component library for developers, designers and product managers.
Tartube - You can download individual videos, and even whole channels and playlists, from YouTube and hundreds of other websites.
Responsive Grid System - Spectacularly Easy Responsive Design
ThumbZilla - Awesome thumb stomping and kicking action game.