jtJava/ForgeModBlockerBungee

A fork of the Spigot plugin for Bungee allowing admins to decide which Forge mods players can use

ForgeModBlocker

A configurable Bungee plugin allowing server owners to block the use of certain Forge mods on their server

Spigot resource: https://www.spigotmc.org/resources/forgemodblocker.45220/