Automatically sort every chest, barrel with  /chestsort. You can also use hotkeys (middle-click, double-click, shift-click and shift+right-click) if you do not wish automatic sorting.

The chest contents are sorted by category and/or alphabetically and stackable things will be stacked. By default, items will be put before blocks. Sorting will work with chests, enderchests, shulker boxes, barrels, minecarts with chest and player inventories. The same applies to using hotkeys.

Wool, Terracotta and other dyeable blocks will also be sorted by color, tools by their material, etc.