The Guava project contains several of Google's core libraries that we rely on in our Java-based projects: collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and so forth.
PGF is a TeX macro package for generating graphics. It is platform- and format-independent and works together with the most important TeX backend drivers, including pdftex and dvips. It comes with a user-friedly syntax layer called TikZ.
fastutil extends the Java™ Collections Framework by providing type-specific maps, sets, lists and queues with a small memory footprint and fast access and insertion; provides also big (64-bit) arrays, sets and lists, and fast, practical I/O classes for binary and text files.
Joda-Primitives provides a library of classes specially designed to simplify the integration of primitives and Objects in Java. Core to this library is a set of primitive collections that directly extend the JDK Collection Framework.
The Enhancements project extends the .Net Framework with multi-purposed and fully-functional modules which enables you to add functionality to your own applications without effort.
Also the modules are built with extensibility in mind, enabling you to extend the framework easily.