In case you don't know, the Garden of Eden Creation Kit is used in the fallout universe to kickstart plant growth in heavily radiated areas. I suggest, if it's not too late in development, to have a few scattered around in hidden vault chests. A block I would use, if a plugin is possible for this at such short notice would be an end portal frame block. When placed, it would kill all entities with no drops within a certain radius, kicking players, if possible, for a longer period of time than usual, say 6 hours. In addition, the GECK will fertilise all land within a set area, turning topmost dirt blocks into grass blocks, manmade structures to their semi respective natural states (i.e. stone brick into cobblestone, cobble to gravel, destroy gravel, turn bricks to hardened clay) as well as destroy any wooden structures in said radius, including chests and other similar constructs. If also possible, it could reduce any radiation gain in that area to 0 (with the exception of water) rads per second. This could be used as a tactical advantage in clan warfare, neutralising one of the bases at the cost of a team member's life, or in neutralising radiation in areas near their own base. Once placed, the GECK destroys itself, turning into an end stone block.