WorldRadiation
This plugin allows you to set worlds where players continuously take damage. Items that mitigate that damage can be configured.
This resource is part of my custom series. You can view the full list
here, prefixed by [Custom]. This series comprises of custom requests from server owners, where I help them out for free and in exchange, I keep all rights to the resource. I am releasing them here for any other server owners who can find a use for them.