eXist is a native XML database featuring efficient, index-based XPath query processing, extensions for keyword search, XUpdate support, and tight integration with existing XML development tools. The database is lightweight and may be easily deployed in a number of ways, running either as a stand-alone server process, inside a servlet engine, or directly embedded into an application.
Libxml2 is the XML C library developed for the Gnome project. The library code is portable (to Linux, Unix, Windows, embedded systems, etc.) and modular; most of the extensions can be compiled out. Libxml2 implements a number of existing standards related to markup languages, including the XML standard, Namespaces in XML, XML Base, Relax NG, RFC 2396, XPath, XPointer, HTML4, XInclude, SGML Catalogs, and XML Catalogs. In most cases, libxml tries to implement the specifications in a relatively strict way. To some extent, it provides support for the following specifications, but doesn't claim to implement them: DOM, FTP client, HTTP client, and SAX2. Support for W3C XML Schemas is in progress. It includes xmllint, a command line XML validator.
Redland is a set of C libraries providing a high-level API for the Resource Description Framework (RDF), allowing it to be stored, parsed, serialized, queried, and manipulated. It has an object-based, modular design and comes with detailed reference documentation and examples. Redland supports all RDF vocabularies such as FOAF, RSS 1.0, Dublin Core, DOAP, and OWL, the query languages SPARQL and RDQL, and all RDF syntaxes including Turtle, RDF/XML, RDF/JSON, RSS, Atom, RDFa, and GRDDL.
XMLDB uses an RDBMS to persist arbitrary XML documents. Due to its storage mechanism, searching for and recalling documents is extremely quick. You can also perform XSL translation on documents with surprising speed. The library can be used in any program to store libxml2 documents. A PHP module is also included, making XMLDB into a complete three-tier Web application development suite.
Raptor is a C library providing a set of parsers and serializers for Resource Description Framework (RDF) triples by parsing syntaxes into RDF triples and serializing triples into a syntax. The parsers support RDF/XML, N-Triples, GRDDL, and Turtle, and via RSS tag soup: XML RSS, Atom 0.3, and Atom 1.0. The serializers support RDF/XML (3 flavours), Turtle, DOT, N-Triples, RSS 1.0, and Atom 1.0. Raptor handles RDF/XML as used by RDF applications such as RSS 1.0, FOAF, DOAP, Dublin Core, and OWL. It can use either expat or libxml2 for XML parsing, libcurl when available for URI retrieval, and is portable to many POSIX systems.
PCGen is a Java (1.5+) -based character generator aimed at supporting OGL role playing games like those based upon the SRD, RSRD, and MSRD (such as Dungeons and Dragons). It is highly configurable by the users, allowing the Game Master to add or remove races, classes, feats, etc., and to implement house rules such as differing class or race restrictions. Level advancement is also supported, with configurable progressions of feats, skills and ability score bonuses. For "at the table" support, PCGen offers a set of GM plugins. Further options allow the user to produce a customized character sheet, which can then be viewed in, or printed from, the user's WWW browser. It can also produce a "party" sheet with the information needed by the GM.