Is your feature request related to a problem? Please describe.
I think the mod listener and blocker is a brilliant feature, but I think it's a bit lacking. The problem is that you can only allow or disallow predefined mods/loaders. This lets any hacked clients that use their own branding join without issue.

Describe the solution you'd like
I'd love to see two things added:

1. A whitelist mode, essentially reversing the modlistener and blocking everything except defined client brands (such as vanilla).
2. A custom mode, where those with the know-how can add channels to listen for mods they'd like to allow/disallow, without having to edit and recompile from source.

Describe alternatives you've considered
One alternative I've considered is forking the plugin, editing files such as this to add custom channels to listen for and recompile the plugin for my own server. The problem with this is I'd have to recompile every time there's an update, and only I would benefit from it.

Additional context
This feature would be greatly appreciated, but I can understand it not necessarily being a top priority considering there are other plugins out there that can do this.

Thanks in advance!

Its a good idea. If you fork and add all of this, lt me know!