I would like to use all characters that are legal on most systems
As a software engineer for many, many years (even prior to the web) who has written and examined password logic for numerous enterprise systems--including the ultra-secure financial services industry--I can tell you that not only is there no "definitive list" of acceptable characters, but there's no such thing as "legal on most systems
". Each and every system is completely independent in this regard.
Sorry to give you bad news :(
Note that you can even use non-English characters on many systems; e.g., the British pound symbol, the German esset, characters with diacritical marks, etc. If you have a US English keyboard and want to enter these characters into the Characters field, its quite simply: you have to use the numpad in conjunction with the Alt key. Try ALT-225, for example. That's the German esset. Note you MUST use the numpad (with numlock on), not the numbers in the top row of your keyboard. Also, this doesn't work on Mac, Linux, or Unix--just Windows.