XP Tome Mod 1.18.2/1.16.5/1.12.2 adds only one new item: XP Tome. It is capable of storing over 1000 XP at once and you can retrieve XP at any time.

Features of XP Tome
It’s able to keep up to 1395 XP by default. You can configure that number via the config. It means that your storage is equal to getting 30 levels on the XP Bar.
It’s easy to use. To store XP, combine Sneak and Right-click. To retrieve XP, choose Right-click.
Existing configuration options (v2.0+)
max_xp: The maximum XP points that the tool can hold.
retrieval_percentage: The percentage of XP that the book will return as a type of cost of using it.
retrieve_until_next_level: Set the value to true to only delete the max XP from the book at a certain time. So, the player can achieve the next level.
store_until_previous_level: Set it to true to just store as much XP from the character’s XP bar until hitting the previous level.
Note! The configuration file for Minecraft versions 1.14.4 and higher are in the serverconfig folder of your world.
XP Tome is a mod that fits adventures and RPGs. It requires Minecraft Forge. There is also an available Fabric version.
Screenshots