You left out Charles I-would you label that an execution or murder?
Although it is entirely by the by, Charles Stuart was the legitimate king of England and Scotland, while the descendants of his deposed son James II, as Josh has pointe out, were deemed Pretenders.
If Oliver Cromwell had assumed the crown, he would have been termed a usurper (and more besides), regardless of your opinion of Charles I.
Charles of course was judicially murdered, as was Louis XVI- which, I think, is how got here. As for his wife and son...
Remind me again, why was it 'The Bourbons' spent 20 years away from France?