Have you explored treasures, and spells that rely on elements outside the game?
A treasure that gives you a glyph of your choice, but you are not allowed to talk, if you do, destroy the item.
Appears pretty innocent on the surface, until you realize that a well placed closing of the eyes or turn of the head means you aren’t aware your opponent is targeting you.
Maybe it’s a 1v1 game and you just keep playing card after card from your hand, letting your opponent know that if they don’t like what you are doing they should just say something.
Or how about a delivery that tells you to take off your sock and try to hit an opponent with it. Although maybe don’t play with your dad (or any dad period) when this card is in the deck.
Or a dead wizard that lets you play on the ground under the table, relying on the honor system that both parties truthfully describe their spells, and take the damage they are supposed to, there is honor amongst wizards right?