• DBIx::Class (and Rose::DB)
• BioPerl (and related technology)
• Catalyst
• Template (and Mason)
• Moose (arguably #1 though not usually specifically mentioned in job posts)
• Not explicitly Perl but seen on job boards in tandem constantly-
  • Testing and QA stuff
  • Sysadmin and deployment stuff
  • DBA stuff
• Encode
• JSON
• XML::LibXML
• DateTime

Your question is open-ended but if you have solid chops in a good amount of those you will find quite a few jobs are available. I listed them in roughly the density they have in my automatic job emails. I recommend something like http://indeed.com's automated mailers. They are highly tweakable.

Update: meant to say: you'll need to whittle down what you want to learn to specifics if you want pointers/links/tutorials.