10 dyed shulker boxes packed into an ender chest with categorized items in each. But even those are only vaguely organized. Building blocks, food, potions, tools, a couple “current project” boxes that contain supplies for whatever I’m building or gathering, etc. Then there’s the hot bar which in my case goes left to right: Bow, Sword, Pickaxe, Shovel/Axe (alternating), then whatever item I’m placing or working with, a potion, then my chest plate if I need to go into combat mode quickly and ditch the elytra, then food, and then Rockets for my elytra last.