CPAN, Comprehensive Perl Archive Network has over 25,000 open source modules available for download.
The Comprehensive Perl Archive Network (CPAN) is an archive of over 25,000 distributions of software written in Perl, as well as documentation for it. It is searchable http://metacpan.org/ or http://search.cpan.org/ and mirrored in over 270 locations around the world.
CPAN can denote either the archive network itself, or the Perl program that acts as an interface to the network and as an automated software installer (somewhat like a package manager). Most software on CPAN is free and open source.
If you are after a list of recommended modules, look at Task::Kensho.