Google Open Source - All of Googles open source projects under a single umbrella
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
Opensource Builders - Find open-source alternatives to commercial apps
Disney Open Source - Explore Disney's Open Source projects
Stylepill - Get beautiful open source UI components weekly
Dev Lake - Dev Lake is a free & open source product analyzing & visualizing the data inside your dev tools, bringing the information you care about to one personalized & practical dashboard.