All items stack up to 64

Config

/trigger bigger_stack_size.config

If disabled in the config, all items will reset when you split them up in your inventory

To choose what items are stackable

Edit this file:

datapack/bigger_stack_size/tags/item/stackable.json

To make certain items temporarily unstackable, e.g. for an item sorter:

Name the item "unstackable" with an anvil

Showcase

Default Stack Size 64 Items

Armor stands, Banner patterns, Banners, Beds, Boats, Cake, Chest boats, Discs, Empty buckets, Empty shulker boxes, Eggs, Ender pearls, Honey bottles, Hanging signs, Lingering Potions, Minecarts, Potions, Saddles, Signs, Snowballs, Splash Potions, Stews, Totems of Undying, Spyglasses, Writable books, Goat Horns, Horse armor

--> All of them are stackable up to 64