cddlib is a C implementation of the Double Description Method of Motzkin et al. for generating all vertices (i.e. extreme points) and extreme rays of a general convex polyhedron in R^d given by a system of linear inequalities.

CUDD is a package for the manipulation of Binary Decision Diagrams (BDDs), Algebraic Decision Diagrams (ADDs) and Zero-suppressed Binary Decision Diagrams (ZDDs).

C-XSC is a libary for the development of numerical algorithms that deliver highly accurate and automatically verified results. C-XSC can do real, complex, interval, and complex interval arithmetic with mathematically defined properties, dynamic vectors and matrices, accurate dot products, predefined arithmetic operators with highest accuracy, standard functions of high accuracy, dynamic multiple-precision arithmetic and rounding control for the input and output of data.

The FFLAS-FFPACK library provides functionalities for dense linear algebra over word size prime finite field.

FLINT (Fast Library for Number Theory) is a C library in support of computations in number theory. It is also a research project into algorithms in number theory. At this stage, FLINT consists mainly of fast integer and polynomial arithmetic and linear algebra.

GAP is a system for computational discrete algebra, with particular emphasis on Computational Group Theory. GAP provides a programming language, a library of thousands of functions implementing algebraic algorithms written in the GAP language as well as large data libraries of algebraic objects. GAP is used in research and teaching for studying groups and their representations, rings, vector spaces, algebras, combinatorial structures, and more.

The AGT package contains a methods used for the determination of
various algebraic and regularity properties of graphs, as well as
certain substructures of graphs. The package also contains a library
of strongly regular graphs, intended to be a resource for
computational experiments.