Powerful Kings And Queens Appeared In Game Of Thrones
Daenerys Targaryen
After the murder of Viserys, Daenerys became the last known living member of the House of Targaryen and the legitimate Queen of the Seven Kingdoms. Her claim to the Iron Throne is one of the strongest than any character in Game of Thrones, but starting her quest to rule on another continent puts her at an early disadvantage. Her dragons, however, gave Daenerys the strength to fight for her claim to the throne, and during Game of Thrones season 7, she came to Westeros like her ancestor, Aegon I. Daenerys allied herself with Jon Snow, King of the North, and together they defeated The Night King and Cersei. With all her enemies dead, Daenerys is the assumed ruler, but her campaign to rule the Seven Kingdoms has made her cruel. Unable to let Daenerys take her place on the Iron Throne, Jon stabs and kills her in the Game of Thrones season 8 finals.
Mance Rayder
Not every King or Queen of Westeros is interested in the Iron Throne. Mance, for example, is a former member of the Night's Watch who deserts the order to live in the Wildlings north of The Wall. In response to the growing threat of White Walkers, he manages the unthinkable and unites the numerous wildling clans, leading them south and gaining the title, King-Beyond-The-Wall. Unlike others, Mance's title as King is bestowed on him out of respect rather than tradition, perhaps making him the strongest claim to rule over his chosen people. In-Game of Thrones' season 4 finale, however, Mance was captured when Stannis' army arrived at The Wall, and in Game of Thrones' season 5 premiere, he was set to burn at stake. But instead, Mance is killed by Jon Snow, who takes pity on his misery and shoots him with an arrow through his heart.
The Night King
The Night King was the leader of White Walkers and they are the supernatural enemy of every king and kingdom in Westeros. Game of Thrones season 6 reveals that the Night King was once a human being, he was the first men to live in Westeros before he was turned by the Children into the very first White Walker. The White Walkers were created to defeat the First Men, but the Children failed to control their own creation. The Night King declared war on Westeros, covering the continent in darkness during an age known as the Long Night. The army of the Night King was finally pushed north by the First Men and the Girls, and the Wall was constructed to prevent the White Walkers from invading again. During Game of Thrones season 8, the Night King successfully breached the Wall and led his forces to the south. A great war began in Winterfell between the armies of the living and the dead, during which Arya Stark defeats the Night King by using a Valyrian steel dagger to put an end to his reign forever.
Jon Snow
While Games of Thrones began as the bastard of Ned Stark, it is eventually revealed that Jon Snow is actually the trueborn son of Rhaegar Targaryen and Lyanna Stark. As such, Jon-whose real name is Aegon-is the rightful heir to Iron Throne, supplanting even his aunt, Daenerys's claim. Of course, although Jon accepts the title of King in the North from the Lords of the North, he has no interest in becoming King of the Seven Kingdoms. Instead, he battles to put Daenerys on the throne, but after seeing how merciless she has become, he destroys her for the sake of the realm and all those she hoped to conquer. Jon is imprisoned for regicide, but instead of being hanged, the newly crowned Bran the Broken sends him to The Wall to take the black again and join the Night's Watch.
Bran Stark
There is no perfect to the Iron Throne after Jon kills Daenerys and deny his title. Actually, the Iron Throne was no longer there. With the lords of Westeros met to decide the fates of Jon Snow and Tyrion Lannister, Tyrion suggested that this council should select a new king and Tyrion gives a passionate speech for Bran Stark to be elected King, claiming that he will be the only King to see, since he is also the 3 Eyed-Raven, and carries all the world's memories. The Council agrees, and in the first election of its kind, Westeros elects Bran the Split King of the (newly formed) Six Kingdoms.
Robb Stark
The North's participation in the 5 Kings War begins with Robb's declaration of war against the Lannisters because of the arrest and execution of his father, Ned Stark. While he marching to the south, the northern bannerman swears loyalty to Robb and crowns him King in the North. This intervention turns Robb's campaign from winning justice for his father into one of the northern successions. The North no longer accepted Joffrey as their ruler, and they wish to become an independent kingdom governed by the Starks, as they had been before the conquest of Targaryen's. While Robb wins every battle, his reign as King ends with his death in Game of Thrones season 3, coming during the shocking Red Wedding events when he is betrayed by Walder Frey and assassinated by Roose Bolton.
However, these are the most powerful Kings & Queens in the Game Of Thrones series. But apart from those characters there were more strong characters who were not kings.