This was a less popular theory, but a good one. Like the Jaime-kills-Cersei supposition, it was rooted in a scene from the books in which the witch Maggy tells a teenage Cersei she will be choked to death by "the Valonqar." The latter is said to be High Valyrian for "little sibling."
In the end, Jon was never even in a position to kill Cersei.
Giant theorists think more hints at this potential twist have dropped through the years. One of the biggest is in "Sigils," a teaser trailer for season 7, which closes with a giant shot of -- wait for it -- a blue eye.
By the end of the finale, it was pretty clear: This was no dream.
Called the "biggest" fan theory about Game of Thrones, this one holds that our resurrected hero is "The Prince That Was Promised," aka Azor Ahai, a legendary, fire-sword-wielding savior figure from the books whose name has not yet been uttered on the series.
Kit Harington told Huffington Post his character wouldn't "pay much attention" to being the prophesied one.
In the finale, we see Jon travel beyond the Wall -- but not as any sort of chosen one.
This theory was nearly as accepted as the Jon-is-Azor theory. There's even a Redditor who made a color-coded chart that showed the princess as the odds-on-favorite. It showed her hitting all the right Azor notes, including a shared talent for bringing stone dragons to life.
We never really got any closure on the Azor Ahai prophecy, but Dany definitely didn't bring peace to the realm.
The reformed smuggler was viewed as something of a dark-horse candidate. But an elaborate theory made a case that the series had hinted at the so-called Onion Knight's destiny going back to when Davos retrieved a cooled, but once-flaming, sword from the sand.
Confirmed: Tyrion Lannister betrays the Lannisters
This theory -- borne out in season 7, episode 3 -- featured Daenerys' army attacking the Lannisters' Casterly Rock. The attack was planned with insider knowledge provided by one of the royal family's own: Tyrion.
Quashed: Bran Stark will lead the Night King through the Wall
Fans thought the the young warg would unwittingly bring the leader of the White Walkers -- and his army -- into the Seven Kingdoms. Bran's arm, marked by the Night King in season 6, would act as a GPS device and show them the way inside.
Now we know the real way that the Night King breached the wall, and it wasn't via Bran.
The ice dragon theory also posited that the zombie would, oddly enough, fight for Jon Snow and the North. The King in the North, who was also resurrected, would be able to tame the ice dragon and ride it.
But during the Battle of Winterfell, Jon Snow spent a lot of time battling the ice dragon.
Bran the Builder -- also known as the first Brandon Stark -- built the Wall and Winterfell centuries ago. This theory suggested that the second Bran would warg into the past to construct the Wall... and tells people his name while he's there.
Remember Gendry, the illegitimate son of Robert Baratheon, who was shipped off on a boat earlier in the series? The rumor that Gendry would make a triumphant return to team with Jon Snow and Co. also came true in season 7.
Perhaps the only thing less surprising to Game of Thrones fans than Jaime Lannister taking the life of his sister would be Tyrion Lannister, another of the queen's brothers, doing the deed. Like Jaime, Tyrion pretty much fits the Maggy prophecy to a T.
Debunked: There's a parallel between each direwolf and its master
One theory about the Starks suggested that the fate of their dire wolves reflects their own futures.
Greywind and Robb were both beheaded. Rickon and Shaggy Dog were killed by Ramsay Bolton and his goons, respectively. Even Nymeria and Arya walked similar paths, both escaping into the wild. But as for Sansa...
Debunked: Arya Stark is dead ... and had been dead for a while
In season 6, Arya kills the Waif in a darkened alley... or does she? The Arya-is-dead theory held that it was actually the Waif who prevailed, and then assumed Arya's identity by wearing her face. This turn of events was hinted at, believers speculate, when Jaqen H'ghar told Arya (or should we say, the Waif?) that she had "become no one."
We doubt that the Waif would have left the Red Keep or attempted to save townspeople of King's Landing. We also don't believe that the Waif would have given up her life as an assassin to explore the world beyond the map.