Is there a plugin that blocks other plugins from working in other worlds? Kind of like per world plugins.
This is impossible. If you have at least 2 players, you can have two loaded worlds at once, so how will the plugins work properly? A disabled plugin is a disabled plugin: it doesn't do anything until it's enabled. I don't know what exactly you want to do, but you'll probably have to ask the author of your plugin to make it multi-world. Edit: Also, please don't make duplicate posts.