I got these because they can go in drawers but I actually just stack them and they will fit any mini pads....from Organize more. I wait for sales. More than I usually spend on organzation, and people can probably create their own version of this. This place makes a lot of stuff that specifically fits into IKEA pieces...lol. You save on IKEA and then spend on them. The price on these did go up.
You can use these for the mini rectangles too (like Ranger archivals)-just turn them sideways.
https://www.organizemore.com/collect.../mini-ink-tray
If you google mini ink pad storage you will see a number of ideas...there seems to have been a plastic box with foam that had inserts that fit cubes that people cant find anymore from 2017? Seems to me a person might be able to make their own of that either with a craft knife and a lot of patience, or just pushing them into a piece of flower foam. I might have done that had I seen that sooner.
Ranger has tins...I am actually surprised at this point they have not released a big one. Theirs only hold 12. They have them for both squares and rectangles.