I am the developer of the Oraxen minecraft plugin. This plugin allows to add new items to the game with a texture pack. It is a spigot plugin but it can be used on bungee networks. There is however a problem:
When a player changes lobby, Oraxen sends him the pack back, even though he might have already loaded the same one on the previous lobby.

This plugin solves this problem by intercepting the pack and comparing it to the one loaded by the player. If it is not different, it stops it.