Apart from the Polish parliament electing kings there was also an elction-kingdom of Sweden. Or at least historians call it that. There was some element of election and acceptance but the process is somewhat hard to understand.

And speaking more of the modern age, the king of Sweden is often seen as perpetually running against a republic. If the royal family became unpopular and the peoples support waned, there would be a republic. With a figurehead president.

Sweden's finest (and perhaps only) collaborative, leftist e-newspaper Synapze.se