DISCLAIMER
Probably
not the answer you want:
I put all cardboard boxes into a plastic bin and threw the bin in a closet.
The handful of TG-16 games that never came with a jewel case have found a new home (a re-purposed
TV Sports jewel case, most likely).
You could certainly still display some of your TG-16 boxes, but they simply aren't practical for storage unless it is long term (years!) and, at that point, your poor HuCards would feel abandoned and neglected.
You could go even one step further and eliminate the jewel boxes:
As for the resealable covers you are looking for... I'm sorry, I don't know where to find them