My vials live inside Mira 13.5 oz insulated food jars. (They stopped making them, but I'd already stocked up enough to last forever.) Thanks to the jar's shape, vials can go in pointing up or pointing down, and once the bottom can't take any more, I start a new layer above. 15 vials fit per layer, so 2 layers means 30 vials per jar, and there's still space left for dessicant packs.
I write on the outside side, the outside top, and the inside top: contents, sender, month and year of receipt, cap color, and how to reconstitute. (these days each vial also gets its own label once tests come back.) Everything from those labels, plus the thermos color, goes into my COA folder. After that, if there's no plan to use it soon, it goes to the bottom of the freezer.
This setup guards against temperature swings. Nothing ever gets knocked around, comes loose, or turns into an anonymous vial in the freezer. Oldest stock is simple to find first. Moisture stays in check. It's dark, and there's one more airtight barrier. Should the freezer die, I have time to relocate them to a different freezer. And if I ever had to grab everything and go fast, it's roughly 10 small pods that would fit easily into something. The pods also just make me happy.