I noticed you didn't mention regexes. There's quite a lot you can learn about them. I strongly recommends Jeffrey Friedl's book "Mastering Regular Expressions" for that one. Nearly everyone can learn a bit (or a bit more ;-) from reading it.
Another book that I strongly recommend is "Higher Order Perl" by Mark Jason Dominus. It changed my way of thinking about programs and programming quite a bit.
- Read in perlmod about symbol tables
- If you don't already know it, read perlsec
- Read the unicode documents like perluniintro and perlunicode
- Go to the list of Saints in our Book, randomly click on a few of them, and look at some of their top 50 voted writeups. You'll find some real pearls there ;-)