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
Open Source @IFTTT - A collection of IFTTT OSS projects.
Code NASA - 253 NASA open source software projects
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.