Cartridge is a Django shopping cart, with a ton of features. It includes features for product popularity, thumbnail generation, smart categories, and more.
FeinCMS is a simple content management system built on Django. It uses bundled content types, and extensions allow it to be as complex (or simple) as you need.
Beego is an open source framework for building applications the Go way. It's easy to use, modular, and intelligent.
Wraith is a responsive screenshot comparison tool. It's well-documented and easy to install.
Justified.js lets you create a justified image gallery with jQuery. It tries to show images at their original aspect ratio, but will crop them if necessary.
Office UI Fabric is a front-end framework for building experiences for Office and Office 365. It's mobile-first, responsive, and quick and simple to get started with.
Formstone is a set of thoughtfully crafted front-end components, rather than a traditional framework. It's responsive, lightweight, modular, and automated.