Hacktoberfest is a month-long event to encouage people to contribute to Open Source projects by creating useful Pull-Requests.

You can use the CPAN Digger to find recently uploaded Perl CPAN distributions that can be contributed to.

There are number of other post such as the one introducting CPAN Digger, the CPAN Dashboard, and CPAN Rocks the explanation of CPAN::Digger, and the post about Hacktoberfest 2019 and Perl.

You can also see the call to participate in the 584th issue of the Perl Weekly newsletter.

Command to run after cloning the CPAN Digger repository if for some reason you prefer the command-line report. 

perl -I lib bin/cpan-digger --recent 1000 --report --days 7 --vcs

I am looking forward to blog posts about the pull-requests you created during Hacktoberfest for any Perl-related project.