Second
Ragnaros the Lightlord is the only legendary on the list not from the classic set. He has managed to find his way in, however, due to his insane board presence. He may not remove an opponent’s threat, but he is far more reliable than his fiery brother. You can easily force him to heal yourself, making his board impact huge. The fact that he creates an 8/8 body afterwards is only a bonus! And if they don’t remove him, his snowballing only continues. He provides an eight health difference the turn he is played, but a sixteen health difference every turn after!
Ragnaros the Lightlord appeared in three of the four Paladin decks listed. It is worth noting that he is second, not third, as he shares this number with another card. His versatility makes him amazing in both Control and Midrange Paladin archetypes. He is easily the best class legendary from any set after the classic set.