2 modes of discovery that ALWAYS require leave of court

What modes of discovery cannot be availed of without leave of court? Obviously, these modes interfere with a person's privacy and the sound discretion of the court must be invoked first before availing of them.

[1] Production or inspection of documents or things under Rule 27; and
[2] Physical and mental examination of persons under Rule 28, which may be granted upon due application and showing of due cause.