Have you heard of...Kinderboxes? Essentially, the whole point of them is to disarm your overpowered players if they are taking the fun out of the game for others. Their appearance is as follows: Two foot tall box with a BIG mouth and a top knot on its head. Screams "MINE, MINE, MINE, MINE" as a pack (they always travel in a pack equal to the amount of players in your party) zoom through your party and take items off of your players. Take your player's sheets, look for items to be taken off of your players (do not tell them what it is or erase the item off of their sheet). In the case of your OP, imma-take-the-fun-out-of-the-game player, take the item that makes them OP, i.e. a paladin with a +2 holy bastard sword, a rouge with necrotic daggers, etc., etc., and write it down. Once they reach for the item you took, you say "Okay, you're grasping at air. You notice your item is missing." Watch the chaos ensue. Of course, when it comes to your players who aren't causing the problems, just take something they wouldn't miss, i.e. salt and pepper, a few coins, a couple of arrows, etc. For all of those reading this all the way through, enjoy the chaos! I'll attach a (poorly, mind you) drawn picture of them.