GitHub is a widely used code hosting platform with a large number of open source projects and code bases. The following are some popular projects and code libraries on GitHub:

1.Linux kernel: Linux kernel is one of the largest open source projects in the world, which contains many core components of the operating system. You can view and learn the source code of Linux kernel on GitHub.

2.TensorFlow: TensorFlow is an open source library for machine learning and deep learning, developed by Google. There are many tutorials and sample codes about TensorFlow on GitHub.

3.react: react is a JavaScript library for building user interfaces, developed by Facebook. There are many tutorials and sample codes about React on GitHub.

4.Vue.js: Vue.js is a progressive JavaScript framework for building user interfaces, developed by EvanYou. There are many tutorials and sample codes about Vue.js on GitHub.

5.Python: Python is a widely used programming language, which is suitable for Web development, data analysis, artificial intelligence and other fields. There are many Python projects and code libraries on GitHub, covering various fields.

6.Java: Java is a widely used programming language, suitable for enterprise applications, mobile applications (Android) and other fields. There are many Java projects and code libraries on GitHub, covering various fields.

7.c++:c++ is a widely used programming language, suitable for game development, system programming, embedded systems and other fields. There are many C++ projects and code libraries on GitHub, covering various fields.

8.Go: Go is a programming language developed by Google, which is suitable for building high-performance network services and distributed systems. There are many Go projects and code libraries on GitHub.

9.Rust: Rust is a programming language developed by Mozilla, focusing on security and performance. There are many Rust projects and code libraries on GitHub.

10.Apache Foundation Project: Apache Foundation is a non-profit organization responsible for managing a series of open source projects, such as Hadoop, Spark and Kafka. You can check the source code of these projects on GitHub.

In addition, there are many excellent projects and code libraries in other fields, such as front-end frameworks (such as AngularJS and Ember.js), databases (such as MongoDB and Redis) and test frameworks (such as JUnit and pytest). According to your own needs and interests, you can find suitable projects and code libraries on GitHub for learning and reference.