AA-lib is a low level gfx library just as many other libraries are. The main difference is that AA-lib does not require graphics device. In fact, there is no graphical output possible. AA-lib replaces those old-fashioned output methods with a powerful ASCII art renderer. The API is designed to be similar to other graphics libraries.
ABL (Abstract Basic List) is a flexible abstract list library defined using the C preprocessor. It allows you to define linked lists of arbitrary types very easily. You also can use these lists as stacks or queues. You can easily define complicated types like a list of lists. It contains a set of functions to work on lists, including higher order functions for filtering and so on. The list includes detailed documentation in texinfo format.
ACCORD is a C library for composition of SEM or scanning helium-ion microscope images with correction of drift. It is able to compose (average) large sets of extremely noisy images that were acquired by scanning charged-particle microscopes at the highest possible speeds (lowest pixel-dwell times). If the images are composed using traditional techniques, they usually become extensively blurry. The technique that is implemented in this software corrects these derogations by pre-shifting the composed frames.