DLT is an extension to the DLV system providing reusable template predicate definitions. It is maintained by members of the DLV team from Università della Calabria.
dlvex is an extension to the DLV system providing access to “external predicates” which are supplied via libraries. It is maintained by members of the DLV team from Università della Calabria and will eventually be integrated into mainline DLV.
dlvhex is a system for answer set programming with external computation sources.
DLV!sual is a small GUI frontend for DLV. It allows you to comfortably view the DLV output in a GUI window. The output will be refreshed automatically when one of the selected files changes, so it’s easy to experiment with DLV by editing the input files in an editor and seeing the output in the DLV!sual window.
Vladimir Sarsakov, Torsten Schaub, Hans Tompits and Stefan Woltran have created an external frontend for logic programs with nested expressions.
NLP-DL is a system for coupling nonmonotonic logic programs with description logics.
James Delgrande, Torsten Schaub and Hans Tompits have created an external frontend for prioritized logic programs.