- apple/swift 32,518 The Swift Programming Language
- arduino/Arduino 5,714 open-source electronics prototyping platform
- libgit2/libgit2 5,708 The Library
- ResearchKit/ResearchKit 4,661 ResearchKit is an open source software framework that makes it easy to create apps for medical research or for other research projects.
- layervault/psd.rb 2,867 Parse Photoshop files in Ruby with ease