So, I was thinking yesterday about how 1.13 and Data Packs will give us custom crafting, and I've already prepared for it, by extracting the default recipes. (Open the 1.12 jar file with WinRAR, extract the Assets folder, explore until you find recipes. :]) I was planning some stuff I wanted to put together for my custom recipes, and was thinking about some speculation I had heard about what level of control it will have, and I had an idea. I call them the "Null Items".

I have no idea how to format this, so here's a list of the items, and what they do.

Null Block – Null Block is a technical block with empty values. Through custom crafting you could craft one of these, but with NBT data preset on it, such as a block texture, hardness value, blast resistance, required tool, and whether or not it obeys gravity or is "polar", like logs and bone blocks, or "angular" like Terracotta. You can choose what it drops when you break it (Itself, a number of some item, or nothing. You can make it drop nothing by default or itself with Silk Touch)

Null Container – This is a tile entity, similar to the Null Block, but instead it is automatically set to be "Angular" and not to obey gravity (similar to how chests work, and this cannot be toggled with NBT code.) You would be able to use the NBT data to control how many slots it has, whether it has a "Wifi Value" (Make it work like an Ender Chest), or if it has a "Backpack Value" (Make it act like a Shulker Box), or if it produces power when opened (like a Trapped Chest, and you can set the power level it makes.) You can choose it's opening animation between "Normal" and "Spinning" (Normal is like a chest, Spinning makes it animate like a Shulker Box.) You would also be able to customize whether or not it works like a Furnace. (Turning this on would ignore the NBT code for having an animation)

Null Item – This lets you make a regular item, like an Iron Ingot or a Diamond. You can use it in crafting, and same goes for any of the other Null Item types.

Null Food – Customizable food!

Null Tool – You can set which tool it mimics, and what it's stats are (damage, attack speed, etc.)

Null Armour – You can set which armour it acts like, and can give it a "Fly Value" (make it act like an Elytra), and having a Fly Value would work with any other armour data you add to it, so you can make an armour piece that also lets you fly.

All of these would be crafted only using a custom crafting recipe, and you would use the recipe to set NBT data for the result. Since an item's recipe file can contain multiple recipes (I've checked, you can), you can use this to add multiple custom items, multiple blocks, containers, foods, or tools, whatever you like, however many of it you need for your map, or to spice up your survival world. Any custom Null Item you make can also be used in crafting recipes (If all the NBT data is the same :]) you you could, in theory, for example, make completely customized armour, using a custom item, made by breaking a custom block, crafted with vanilla items, using this hypothetical fun little idea.

If you have anything you want to add, please let me know, I really want to make this idea as cool and fun as possible 😀