Continuity mistake: When Grey Worm leads Tyrion to the Dragonpit, as they pass the column of Unsullied their long individual shadows are directly to their sides, but in the next shot the Unsullied are seen in the background and the shadows are entirely different. (00:46:00)
Continuity mistake: When Arya stabs the Night King it's high on his chest, piercing his leather armor. In the next wide shot, the dagger is lower and not in the armor.
Continuity mistake: When Daenerys is dead she has blood underneath her back and hair, and as the camera is above her, her right arm is curved or bent a little. When Drogon picks her up her arm is now straight and despite the blood on the ground she seems to be completely clean. No blood on her back, hair or scarf. Then as Drogon flies away, how on earth did he pick her up with his left hind leg? Did he twist his leg 180° to pick her up with his front claw?
Continuity mistake: While Jaime and the High Sparrow are standing beside Myrcella's body in the Sept, in the overhead shot of Myrcella her right hand is placed over her left hand, but in other shots it's the opposite way. (00:18:30)
Continuity mistake: When Daenerys dies, in the close up her head is parallel to the ground, looking up at Jon. Cut to a wide shot and her head's hanging much further backwards, plus her eyes are suddenly closed.
Revealing mistake: At the beginning of the episode, Robb and Blackfish Tully are pushing Hoster Tully's funeral boat down the river. When they climb back onto the dock, there is already a trail of water going from the steps and ending where Robb ends up standing. None of the other characters standing on this portion of the dock have wet clothes, meaning none of them went into the river, indicating that the trail of water was from previous takes.
Continuity mistake: When Dany dies, the blood trails coming from her mouth and nose are pale in some shots and dark in others. They also appear to change position slightly, but that might just be the camera angle.
Continuity mistake: When King Robert arrives at Winterfell, the wide leather straps of his cloak are crisscrossed with his left over his right, but when Robert and Ned walk inside the crypts, Robert's straps are crisscrossed the opposite way, with his right over his left. The shots are not flipped.
Continuity mistake: When Bran is taken from his horse in the woods, there are 3 wildlings that attack. The first Rob cuts his throat, the second, Rob is holding the female wildling by the hair, he then spears and kills the third with his sword and the very next frame the 3rd wildling is then holding a knife to Bran's throat, unharmed. (00:11:15)
Visible crew/equipment: At the Wildling camp, before Jon and Ygritte go into the cave, there is a modern building, and clutter visible in the distance.
Character mistake: Davos advises Grey Worm to claim land in the Reach and start his own house. Since Grey Worm is a eunuch, he cannot start his own house, as he cannot father children to pass his name and lands onto.
Other mistake: When Ned is about to behead the Night's Watch deserter, the deserter whispers, "Forgive me, Lord..." No major religion in Westeros refers to their deity or deities as 'Lord'.
Suggested correction: But Ned is a Lord. His Lord even. He asks Ned for forgiveness.
Battle of the Bastards - S6-E9
Character mistake: When Theon and Yara are given an audience with Daenerys, Tyrion remarks to Theon that when they last saw each other at Winterfell, Theon was making jokes about Tyrion being a dwarf. The mockery was actually the other way around: Tyrion mocked Theon for being a glorified and subservient hostage of the Starks, as well as taking potshots at the foolish strategy of the Greyjoy rebellion.
The Mountain and the Viper - S4-E8
Continuity mistake: When Oberyn first tells Gregor that he will make him confess to raping and killing his sister Elia and her children, he is holding his spear with both hands. In the next shot, he's holding it with just one hand.