liblist provides a generic C API for manipulating and traversing doubly-linked lists. It uses opaque handles to hopefully allow a stable ABI in the future.
FTL is a generic system-level application programming library written in C++. It features a very broad abstraction of system interfaces, provides many useful generics, and has a very small compile-time overhead.
The Horde task list manager.
A Java class library for importing and creating PDF documents.