[scryfall]Yargle, Glutton of Urborg[/scryfall] is an interesting case. MaRo has communicated to us that it’s more or less a joke. Something they put in Dominaria just to have vanilla legend in there.
However, it is quite unique. How many legendary creatures with such a high power with that mana do you have? Actually, only one bests our little frog spirit: [scryfall]Lord of Tresserhorn[/scryfall]