This plugin was created to provide special tools for donators or people with a rank on a server so that they can have a small extra benefit while mining. While not having to add very big plugins that eat your server resources.
You can create your own special tools with your own set rewards!
This plugin is lightweight and might be just what you were looking for.
Get extra resource drops by just mining with a special tool
As you can see there are a few things that can be adjusted such as the tool, drop chance, reward and the minimum and maximum amount of resources you can get every time you get lucky. You can get the Midas tool by running /specialtools Midas or a different name if you want something else.