Check out storage supplies for scrap book pages. They are usually 12 x 12 inches though so might not work if rulers are larger. For example these sheets would store in a note book and you could label each pocket. Just find the ones to coordinate with your rulers.
Another holder that might work too.
https://www.scrapbook.com/store/sr-s...d+organization
Another holder that might work too.
https://www.scrapbook.com/store/sr-p...d+organization
The office supply stores also have divider pockets with zip-lock tabs.
Hope that helps!