On a figure in the original packaging, the card is often worth more than the plastic. A crease in the blister card is a different condition. In the overview Security for collectors this sits between toy and paper.
What gets ruined without a thief
Sun bleaches the card. Damp ripples the cardboard and loosens the glue of the bubble. A stack in the basement presses the bottom card crooked. You store upright or flat with little weight on top, dark, dry, not against the exterior wall that sweats.
When someone comes
Boxes marked "Toys" are a grab for many offenders and a target for some when the brand on the box is readable. You take the few very expensive cards out of the big stack and put them in the place that fits the sum: a cabinet, if the price calls for it, otherwise on top of the stack, where no water stands, and not in the hall.
The folder
Maker, year, variant, whether the card is free of creases, receipt for the expensive ones. A photo of the front. Variants that differ only by a small imprint, you write down so that you can still tell them apart in a year.