Plugin Name: GreatKits [1.8 - 1.13].
Spigot Link: https://www.spigotmc.org/resources/greatkits-1-7-1-13-full-config-kits-plugin-save-and-load-inventory-with-commands.44535/
Price: Free.
Personally I have used this plugin a lot in my experience configuring minecraft servers, it is an excellent plugin to create, edit kits, it also stores custom items, custom nbt, etc. It is certainly much better than the kit system built into the Essentials Plugin.