Useful Backpacks adds three tiers of inventory expansion in the form of backpacks. The small pack adds just a minor increase to your inventory and it’s accessed simply by right-clicking it in your hand.
Here you can transfer over any excess items you no longer need quick access to or anything you see fit. So with that the next upgrade is the medium pack offering a bit more storage.
And then a much larger upgrade is the large pack.
These packs are like carrying portable chests with you to maximize the somewhat lacking inventory in standard minecraft. This mod also allows you to craft the packs in any color wool the game comes with so you can coordinate!
It also requires an additional API found here.DownloadForumInstall Guide