These are custom inserts I designed to store my Beyblade X collection, utilizing a cheap $12 case on amazon I found that was just a bit undersized. They're made and sold by several vendors and frequently go on sale; I got mine on sale for like 2/$20 at one point.

Here's a link to the specific one I bought:
https://a.co/d/gnpDVdW

The case is just short 5mm of being able to hold them in fully assembled. You can assemble the case in a few ways depending on your tastes; I've designed custom Tip storage inserts for the smaller holes at the bottom of the case, which would allow you to hold a total of 30 beys max in the case. Alternatively, if you cut a few holes into the bottom of the case, you can hold a max of 27 beys fully assembled.

I did this using a 20mm hole saw attachment for a drill, though you could also achieve the same results with a regular large drill bit and some flush cutters (a little gnarly, but it'll do) or even a Dremel if you're crafty. Optionally, I recommend a deburring tool to clean up your cuts but if your hole saw kit isn't literally the cheapest one on Amazon like mine is, you may not even need it.

And as a precaution as we move ahead, though I show myself marking the holes for all three inserts at a time, I actually recommend you do one row at a time and then remove them. Once all three rows are in the case, it's intentional a bit hard to remove them. Doing one at a time will make removal much easier.

First, place all three inserts into the case of either the 4 or 5 bey sets. As they fit fairly snug, I tap mine in lightly using a small rubber mallet to get it flush to the bottom. I than use a silver sharpie and trace the hole, then remove the inserts using a metal spudger. I personally chose to do the 4 slot holes first, then the 5 slot after, drawing both sets of holes on one side.

Now we have a template for the holes we need to cut. As stated above, I utilize a cheap hole saw attachment for a drill. I chose to deburr the holes after to clean them up a bit, but it's totally unnecessary.

After all 27 holes are cut and cleaned, reassemble both sides of the case with the inserts in alternating patterns; 4-5-4 or 5-4-5. The inserts are designed with inset holes on the bottom which should match up with your insert on the reverse side, giving the tip the extra ~7mm or so it needs to fit in the case latched shut.

You can alternatively hold 18 beys and two launchers in a case as well if you wanted something that was a complete solution for travel; the string launchers with grips at the bottom will fit fine if you instead cut a much larger hole for the launcher's grip mechanism in any of the sections. You could also store a ripcord launcher without the grip attached as well, though its a bit shaky. I may revisit this at some point to create inserts for each launcher type; probably after the sword launcher releases later this year. No promises though!

Last thing I should note; if you're utilizing the top segment of the case, you'll need to mirror the "4-slot Top Side" and "5-slot Top Side" pieces in whatever program you create your printer files with.