The collection includes:

– Michael Barr's diagxy package designed for general usability in a variety of mathematical disciplines;
– François Borceux' package which is specifically aimed at category theory diagrams;
– the circ circuit-diagram macros;
– Pedro Quaresma's dcpic macros for commutative diagrams, using LaTeX picture mode;
– Anders Svensson's kuvio macros for commutative diagrams, using dvips “PostScript \specials”;
– Paul Taylor's long-established commutative diagram macros, which are designed to provide high power in a standard (La)TeX environment; and
– Kris Rose and Ross Moore's xypic package which can be used for a variety of graphs and diagrams.

To download, or to read documentation of a package, follow the link above to the package's more detailed catalogue outline. The archive does not offer direct facilities to download this collection of ‘competing’ packages as a single whole.

The author is The CTAN team.