You can also use:
pkg prime-list
There are predefined aliases like that in /usr/local/etc/pkg.conf
Tip:
(regularly, automatically) Creating a simple textfile (e.g. pkg prime-list > my_installed_packages.txt) I recommend to be part of your backup plan.
It's pretty handy if you need to set up your machine new, or another, likewise machine: Simply let a script install all packages from this list. No need to remember. No things turn out later to be forgotten.
