Simplicity is a lightweight modular Web development framework. It is designed with a tight core providing centralized configuration, caching, auto loading, session handling, and a simple ORM. All other functionality is provided by modules which can be loaded in module chains. Each application can have multiple chains.
eXtcos is an extensible JVM component scanner, similar to the component scanning feature of Spring. It is a small library solely focused on the task of class path scanning. It provides an easy-to-use query language for requesting the classes. This is a refreshing change to the boiler plate code you need to use the Spring classes for your own needs. You can get several different kinds of classes with just one query. You can use eXtcos for finding plug-ins for your application, classes meant to be run inside your container or framework, and the like. eXtcos is basically a base library on which other applications, containers, and frameworks can depend on.
D:GameVFS is a minimalist virtual filesystem library for the D programming language oriented at game developers. It provides an easy-to-use API for filesystem-independent file/directory manipulation. It supports basic VFS functionality. Files and directories can be created, read, and written, but not deleted. There are no security features (e.g., D:GameVFS can't handle a situation in which a file it's working with is deleted outside the program).
OnPosix is a tiny library to abstract POSIX mechanisms to C++ developers. Most features offered by this library can be found either inside the Boost library or in a library compliant with the C++11 standard. Unfortunately, however, for some embedded Linux devices, these libraries cannot represent viable solutions, due to the lack of memory space (for the Boost libraries) and the lack of a new C++ compiler (e.g., on Xilinx MicroBlaze). On these platforms, the OnPosix library represents a good and cheap solution to have object-oriented POSIX mechanisms. The library offers support for threads, mutual exclusion, sockets, logging, timing, etc.