Not only can every aspect of the rules be altered in some way over the course of a game of Nomic, but myriad variants also exist: some that have themes, begin with a single rule, or begin with a dictator instead of a democratic process to validate rules.
One spin-off of a now-defunct Nomic (Nomic World) is called the Fantasy Rules Committee; it adds every legal rule submitted by a player to the ruleset until the players run out of ideas, after which all the "fantasy rules" are repealed and the game begins again.