EnchantLib is a spigot library for adding custom enchantments.

Features

• Custom Enchants work just like vanilla enchants
• Automatically works with loot generation
• works with anvils, enchantment tables, grindstones and smithing tables just like you would expect
• No special commands needed for giving custom enchants to the player
• Allows Custom Enchantment plugins to work together

Wiki
https://github.com/BoyStijn/EnchantLib