Google Guava, a popular open-source library developed by Google, offers several lesser-known features that enhance Java development by improving code quality and developer productivity. Beyond its well-known collections and caching capabilities, Guava provides utilities such as unsigned primitives, which were available before Java 8, and MurmurHash, a fast, non-cryptographic hashing function. It also includes InternetDomainName for domain name validation, ClassPath reflection for inspecting Java code, and CharMatcher for string manipulation. These features, which are utilized by companies like OverOps, demonstrate Guava's ability to streamline common development tasks and improve workflow efficiency. Guava supports Java 6 and above, offering a range of utilities that are valuable for various projects.