As I understand it, copyright applies to creative expression and not for examples rules of games. Does this also apply to the ISO standards (example, costs CHF 158)? For example, could one re-write the standards in one's own words and sell them in competition with ISO? Or is there something that would prevent this, perhaps something like Copyright in compilation?
Expression vs Idea
As I understand it, copyright applies to creative expression and not for examples rules of games.
That is not correct as stated. Game rule, or more exactly the fixed expression of a set of game rule (what one finds in the package of a commercial game, or in a book such as Hoyle's Rules of Games, can be and usually are protected by copyright. What is not protected is the ideas expressed in a set of rules. These are sometimes called "game mechanics". For example it is a rule of bridge that 13 cards are dealt to each of 4 players. That is a fact, and so is not protected by copyright. But the exact wording of the official Laws of Duplicate Bridge is protected.
"creativity" vs "originality"
Many things that might not be considered very creative are protected. US Copyright law calls not for creativity, but for an original work. The concepts of "creativity" and "originality" have a significant overlap, but are not at all the same.
For example, a person might watch a baseball game and write down play-by-play account of it. That might not be very creative, but it would still be protected by copyright. But the event of the game are facts, and not protected. Someone else might describe the same game in different words, covering the same facts, and that would not be copyright infringement.
Another example. A person writes a scientific paper describing in detail a series of chemical experiments and the results obtained. That is not very creative (although the design of the experiments might be). It would, however, be protected by copyright. But the facts and ideas would not be protected. Another person could desacribe the same experiments in different words, and that would not be an infringement of copyright.
In extreme cases, such as a basic recipe, there is no expression temperate from the facts. In such a case the "merger doctrine" applies, and there is no copyright protection at all.
Standards, such as ISO standards, are normally protected by copyright. But the ideas expressed in them are not. And since standards are highly factual, the protection afforded to them is particularly narrow. But when one is testing compliance with a standard, the exact words of the standard may be important. A compliance officer is not likely to accept a paraphrase as a valid substitute.
Standards in Laws
The actual text of laws (and regulations), however (Federal, state, or local) is never protected by copyright. All are in the public domain. So when a law incorporated and reprints a standard, as is often done with fire and building codes, anyone may freely reproduce the codes as set down as part of law, even through the code has been copyrighted and indeed registered, as long as the source is the text of an enacted law or regulation.
After reading the Copyright Act of 1976, §102 (b):
"In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work."
I understand that there are no copyright in a standard published by a standards body. The reason is that standards are ideas, procedures, processes, systems, methods of operations, and so they can't be copyrighted because of the merger doctrine, as even if they contain an original expression, because of the limited ways those standards can be expressed and still be considered the same standard and not a deviant standard. Also, a standard's intended purpose is to be used by all, so restricting it with copyright restrictions is against its purpose: we would have many competing standards (de jure and de fact) to do the same thing and so we wouldn't have a standard at all (oh, wait, we already have it, just think of office software documents, spreadsheets and presentations).
Of course one can protect him/herself against decisions made by judges that don't agree on this by rewriting the standard, but then risk not being the same standard.