Items such as bandages, biscuits, small water bottle, could stack up to 2, 3 or more per slot, such as ribbons, cables, metals, etc.
• Since they are items that heal little HP and relatively occupy a good space when carrying a large amount.
• Chemicals too, as it's one of the only crafting items that doesn't stack.
This suggestion was taken from my review and translated into English (https://steamcommunity.com/id/blackthug2/recommended/1789480/)