Harmony
Harmony is a library designed to simplify the process of creating Minecraft modifications. This tool offers numerous ready-made solutions and simplified methods for performing standard tasks that mod developers encounter.
The library includes convenient tools for registering various elements, localizing texts, customizing user interfaces, working with items and their stacks, processing NBT data, sending messages to players, using mod identifiers in a universal way, creating timers based on game ticks, managing mod files, working with achievements, and much more.
For those who want to delve deeper into the library's capabilities and learn how to use it effectively, it's recommended to study the source code in the project repository.