Keeping them in stacks of 6-8 is a very good way to store and carry filters.
Indeed, I do the same. I use a lens cap on one end and a plastic cap from a postage tube on the other - Protects the filters from grubby fingerprints and the threads from damage when rattling around in the bottom of a bag.
Beats fishing through a box of loose filters at the flea market.
Any 55mm Yellow filters in there. No.
I think there is.. These are all 52mm. They have all kinds of filter. I found an IR filter in the stack and later when I was checking out, the salesperson was like damn it why did I put this in here, I could've sold it for 50 bucks. Lol.. Anyway, it's 3 bucks each. If you'd like to buy some, I can get it for you.
That filter test is pretty cool, I've always wondered about that. Also I think I see your ir filter, 720nm near the bottom of the stack. The top one from Germany might be B+W or heliopan, my favorite filter brands, all their filters are great.