1.21.1: Fabric and Neoforge.
1.20.1: Fabric and Forge. Later versions are part of Season 2.
Older versions are not maintained.
Mod version 2025 and later is part of Season 2.
On Fabric 1.20.1, users of Sodium may need to install Indium, or models will look weird
On Neoforge, enable the "NeoForge Light Pipeline" in Mods -> NeoForge -> Client settings -> NeoForge Light Pipeline

Packages adds packages, which can hold 8 stacks of one item.

Construct Packages out of any solid block.
Insert and remove items by clicking the front face. No need to use an empty hand.
Hold CTRL to completely fill or empty a Package with one click.
Interact with Packages in your inventory too, just like a Bundle.
Make a package "sticky" so it won't forget its contents when empty.

The catch: Packages only hold 8 stacks. There are no storage upgrades. The size is not configurable. But packages can nest inside each other, and even stack when they contain the same contents!

Other than their size, Packages behave like cheap shulker boxes. Measure with a comparator, crush with a piston, and dispense with a dispenser; shulker box loader and unloader designs work great on Packages.

A double chest with several packages in it, containing common vanilla materials, with varying fill levels