A low-level custom items API (as the name might suggest) for LabAPI or EXILED. Zero bloat, you have full control over everything in your custom items. Info on how to use it can be found in the README and in the Examples folder of the repository.
Repository: https://github.com/3m377/LowLevelCustomItemsAPI
Latest release: https://github.com/3m377/LowLevelCustomItemsAPI/releases/latest