Forge replaces the vanilla registries with its own registries that are synchronized with the registries on the server, and if there is something on the client that is not on the server it will be removed from the client. This mod disables the registry synchronization preventing this. This mod also prevents disabling if you have mods installed that also require installation on the server.
This is a free and open-source project; you can include it in your mod pack as long as you provide attribution!
