Second-Third
If Sylvanas is a staple of Hearthstone, Ragnaros the Firelord is the iconic legendary. Back at launch nearly every deck ran Ragnaros. His power is fairly obvious, able to deal with large threats while leaving one behind. Because he affects the board immediately, he deals eight damage and then often trades one for one. He fell out of favour during Secret Paladin’s reign, because every deck ran many tokens. However, since standard he has regained his throne, dealing with the many present threats.
Ragnaros was present in eight of the decks we analyzed. He is listed as second-third because the next card also had eight. They are listed alphabetically, Ragnaros is not worse than the upcoming card in any way.