Is there a consensus on keyboard shortcuts?

No, there is no 'official' consensus. But software developers do want to make sure their programs are easy to use, so they tend to mimic what has been adopted as the common-practice. CTRL + C will almost always be some form of copy within the context of your application, just as CTRL + S will almost always be some form of save. If you want to please your users, you make your program as familiar as possible.

"Definitely not. There is no consensus at all, even between applications of Microsoft. It's not only that developers can choose whatever they want to implement their shortcuts, and even they can choose not to implement some of them.

Other problem is the language. In English ""ctrl+S"" could be a good shortcut for ""Save"", but for Spanish this should be ""Ctrl+g"" (guardar) and it is in many programs.

However, there are certain rules, as you probably know, but there are not unbreakable laws."