Google uses a variety of fuzzing techniques in their development process. They have publicly shared a repository that encompasses tutorials, discussions, research proposals and other items related to fuzzing.
Within this repository, you will find resources touching on topics such as evaluating the quality of a fuzzing target, fragmenting inputs generated by fuzzing tools, creating fuzzers that recognize specific structures, constructing fuzzing targets, etc.
Repository: https://github.com/google/fuzzing/