There are many resources available for Traditional Notation, known also as Western Notation and simply as “music” writing. The Music Publishers Association has created a valuable document:
It offers in one document the list of implemented and accepted practices used by music publishers for decades. In many instances, designers of alternative notation systems will find guidelines that apply to their systems.
A professor at Indiana University has a Web page listing many borderline cases in traditional music notation: Extremes of Conventional Music Notation. This can be useful to notation inventors in considering various limits that they might want their new systems to handle. Don’t overlook the illustrations.