What if, when you wanted some items that you don't use very often, you could reach for a container IRL and take them out of there for use in-game?
This is my idea for a mod that I would love to see created: adds a storage block which assigns stacks of items to alphanumerical addresses (i.e you open the block GUI, move the stack of items into it then scan in an object to store them in - these can be given nicknames for easy identification). A file in the .minecraft directory then remembers the items assigned to each address, and they are removed from the game. Something that could be enabled in config is allowing objects to be transferred between saves in this way. This could obviously be used for cheating, so maybe in the block GUI, you add a flag to an object to say whether it is world-locked or allowed to be used on any world (that has the IRL storage mod).
In this post, I use stack to mean anything from 1 to 64 of the same item and object to refer to a real-world object with an address assigned to it.
Here's the out of world bit: using either QR codes/barcodes/etc on stickers on real world objects, you can scan these objects into game (with a camera by default) when in the block GUI. Items are then "stored" on those objects. To get them back in game, you scan in the object they are stored on again and they appear back in the GUI of the block.
To avoid early-game overpoweredness of this feature in Survival, let's say you have to craft an in-game chest for every real-world address you use, and the crafting recipe for the block includes something like gold/redstone/obsidian.
For automation-lovers, maybe you could hopper items in from the top/sides, which are stored one stack at a time every time you scan in an object (although you'd surely have to have the block GUI open to activate the camera/address input bar). If the object contains a stack and a hopper on top contains a stack, the block will empty the object's contents if there's a hopper below and be filled by the first stack in the above hopper.
As for scanning tech, barcodes and QR codes are the only digital representation media I could think of, and I don't know how the scanning would work (opening the webcam in game somehow?) but I think at it's most basic level, it could be done by manually entering alphanumeric addresses in the block. Maybe depending on your computer hardware, you select in config how you want to input objects into the game (might require some extra complicated API stuff, so not absolutely necessary)?
If anyone has anything to contribute to this idea or, better still, can make it happen, please comment below!