From my last game (a simpler romp):

May no longer determine if the newly acquired basilisk-hag minion still can petrify people with a gaze by staring deeply into her eyes.

May no longer let the party create their own plan for capturing a spy in town, have them come up with three different plans from around the table, not discuss in character or out of character what to do (while they had full opportunity to), then attempt 3 different kidnappings at once while incurring property damages in the thousands of gold and one player character death along with the spy. There must be at least 2 player character deaths next time.

The Sled of Far Traveling was for conveniently getting from place to place quickly. May no longer use it to bypass half the encounters (or in busy marketplaces).

From a friends game:

May no longer have the character with 20 intelligence and 18 wisdom, upon joining the church of a god of reasonable undeath that requires the removal of an organ to join, attempt to remove his own brain with a gutting knife.

May no longer have the same character start out the heist session by telling the leader of the temple we were robbing about the heist, while in full regalia of a rival god that was laying low about how much they hated the target.

May no longer have the same character, upon being caught with the book that explains where/how to get the object of the heist, tell his captors that he has the book and just found it on the side of the road.

May no longer, once the same character came back to a town in high alert due to an "attack by a rival god" in a golem body he made as a backup clone, as the dragon ruler of the temple was screaming the name of the rival while circling the city in rage, start his first conversation in a bar full of frightened peasants with "So I just met rival god and he's not very happy with me now that I messed up his relationship with Bahamut."

May no longer start a planar war over something that was supposed to just get dug out of the latrine and be done with.

(Not my character, luckily)