Void Key

You create a personal interspatial storage, which lasts a year and a day. This storage is interspatial, invisible, and contains a 10-foot cube's worth of space. While this storage lasts, you can use a bonus action to send an item you are touching into the storage, as long as it fits, or call an item from the storage into an unoccupied space within 5 ft of you or into your hand. There is no weight limit for this storage. No magical items above common rarity may be sent into this storage. You can also use a bonus action to make a portal up to 10 feet and greater than 1 inch in diameter that leads to the storage(closing this portal has no action required) within an unoccupied space within 20 feet of your position. If the portal is ever more than 20 feet from your position, it closes. The storage cannot be dispelled by dispel magic, but while its caster is inside or ends their turn inside an antimagic field, no items can be placed into or taken out of the storage, and all portals created by the storage close, with anything inside them at the time taking 1d6 force damage and ejected into the closest unoccupied space. The storage contains up to 8 hours of air. For every minute the portal is open, a number of hours of air equal to the portal's diameter, divided by 10, is restored.(minimum 1 minute of air for smaller portals)

At Higher Levels. For each spell level above 1st this spell is cast at, the space inside the storage increases: the cube increases to a 20-foot cube(8000 cubic feet) at 2nd level, a 30-foot cube(27000 cubic feet) at 3rd level, and so on. The portal's diameter also increases by 10 ft each level. For every 125 cubic feet added, the storage contains an additional hour of air.   In addition, you gain additional benefits at certain spell levels:

2nd level: The duration increases to 3 years, and the portal's range increases to 30/40 feet (the smaller number is how far away the portal can be upon creation, the larger number is how far away you can be from the portal before it collapses). 

3rd level: The duration increases to 5 years, the portal's range increases to 40/60 feet, and uncommon magic items can now be stored.

4th level: The duration increases to 7 years, and the portal's range increases to 60/90 feet.

5th level: The duration increases to 13 years, the portal's range increases to 90/120 feet, and rare magic items can now be stored.

6th level: The duration becomes permanent, and the portal's range increases to 120/150 feet.

7th level: The portal's range increases to 150/450 feet, and very rare magic items can now be stored. 

8th level: The portal's range increases to 450/900 feet.

9th level: The portal's range increases to 1 mile or sight/1 mile or sight, and legendary magic items can now be stored.