XML-Grammar-Fiction is a Perl package that provides processors for lightweight markup languages and corresponding XML grammars for writing prose (e.g. stories, novels, and novellas) as well as screenplays. The XML grammars can in turn be translated to XHTML and DocBook/XML. XML-Grammar-Fiction currently offers only very basic functionality, but has good support for UTF-8 and allows one to write bidirectional texts conveniently. It is still under development and may exhibit some quirks.
Math::GSL is a Perl API to the GNU Scientific Library, which contains a large set of tools for writing scientific computing applications, like statistical distributions, special functions, random number generators, linear algebra, numeric integration/derivatives, FFTs, wavelets, and much more.
ExifTool is a platform-independent Perl library plus a command line application for reading, writing, and editing meta-information in image, audio, and video files. It supports many different types of metadata including EXIF, GPS, IPTC, XMP, JFIF, GeoTIFF, ICC Profile, Photoshop IRB, FlashPix, AFCP, and ID3, as well as the maker notes of many digital cameras.
WebDyne is a dynamic content engine for Apache or FastCGI servers such as lighttpd. It allows Perl code to be linked or embedded into HTML pages, selective rendering of HTML sections within pages based on logic, and much more. It supports features such as templating, and selective caching of dynamic content to minimise server load and increase throughput.
AnyEvent provides an identical interface to multiple event loops. This allows module authors to utilize an event loop without forcing module users to use the same event loop (as only a single event loop can coexist peacefully at any one time). The interface itself is vaguely similar but not identical to the Event module. On the first call of any method, the module tries to detect the currently loaded event loop by probing for an already-loaded event loop, such as Glib or Event. The first one found is used. If none is found, the module tries to load an event module, and failing that, it will fall back to an optimized pure Perl implementation.
Gtk2::Ex::DBI is a Perl module that is used in conjunction with Gtk2::Perl and Gtk2::GladeXML to give data-aware "form" functionality. The programmer creates a database form with Glade2, and then creates a Gtk2::Ex::DBI object, which then "binds" a DBI data source to the form, managing querying, navigating records, applying updates to the database, and error handling.
Config::Maker takes a file with data in simple hierarchical format (similar to BIND and DHCP configuration files) and several templates, and produces the text by filling in the values. It is mainly useful for creating related configuration files. It can be used to generate firewall configuration scripts, DNS zone files, DHCP configuration files, a reference from a single file with all users and machines, etc. It's useful when you are not satisfied with keeping information synchronized in several places, but don't want something as complex as cfengine. Snippets of Perl can be used if all else fails.