Run a search for molle gear, I am assuming that is what your pack has but I did not read any links about the pack.
Surplus places will have surplus molle stuff. Now and then they have what you want at a good price.
You can take alice clips out and use 550 cord to attach stuff to the molle loops.
Molle is very common, some companies make seat covers so you can cover the back of the seat with pouches and for stuff like wranglers with cute little tailgates some people make organizers with molle loops.
Once you start running searches you should run into all sorts of options for converting what you like over to molle.
Some people just buy stuff and make their own adapters as well, there are specific alice to molle adapters I think but 550 cord is something everyone here should have by the spool.